Eight games in, it was Manchester who was setting the pace in the 2011/12 Premier League title race.
City had won seven and drawn one of the opening eight matches, while United were just two points behind in second spot.
The 'Noisy Neighbours' were turning up the volume, so surely this was a chance for defending champions United to reassert their city dominance?
Mario Balotelli had been in the headlines on the run up to the game for allegedly setting fireworks off in his bathroom – just one of the many bizarre moments our beloved Italian striker was involved in during a three-year stay.
This Manchester City, however, were the real deal.
The FA Cup win over Stoke five months before had ended a 35-year wait for silverware, but could Roberto Mancini now guide his talented squad to the holy grail of the Premier League title after a 44-year wait?
City had scored 27 goals in the first eight matches and were averaging more than three per game, as well as keeping things tight at the back.
There was steel, intelligence and technique in this City side and United knew it – but the fact that they’d only beaten once in their own back yard by the Blues in 38 years weighted this game slightly in the Reds’ favour.
“The main thing was we’d made a great start to the season, but before the game there was a furore about Mario and the fireworks in his bathroom or something,” recalled Gareth Barry.
“The confidence was already there and we were scoring goals, but we didn’t change anything for that game. Everything just sort of fell into place on the day, really.”
Joleon Lescott’s central defensive partnership with Vincent Kompany was the bedrock of the team, with Micah Richards getting the nod over Pablo Zabaleta at right-back and Gael Clichy preferred over Aleks Kolarov.
“It was funny because we were playing 4-4-2 at the time with Samir, Gareth, Yaya and David in the middle but Mancini changed it for that game and put James Milner in over Samir,” said Lescott.
“We didn’t do any special session in the week before. The training methods were basically the same, but it was at a time we were regularly putting teams to the sword.
“We didn’t need to go into too much detail because the United players were already high profile and nobody needed to say Wayne Rooney is a fantastic player capable of scoring wonder goals – we knew how good they were.”
So, was there a rousing pre-match speech from the-then 26-year-old Vincent Kompany?
“No, there was nothing like that back then – obviously, Vinnie was a leader, but we had a lot of leaders at the time,” said Lescott.
“We had Yaya Toure, David Silva – a World Cup winner – Gareth Barry, Nigel de Jong… but there was also Micah Richards who had come through the ranks and the game meant even more to him. Micah and Gael were all over it beforehand.”
And kit manager Les Chapman had planned a special surprise should Mario find the net against the Reds…
“I didn’t have a clue he had the t-shirt on and I think it must have been something Chappy came up with,” said Barry. Lescott, on the other hand, was well aware of the plan.
“Yeah, I knew Mario had the t-shirt on and Chappy had told him he couldn’t take his shirt off and he just needed to put it over his head so he wouldn’t get booked,” said Lescott.
Had he failed to find the net that day, nobody other than those on the inside would ever have known, but this was a day when all the stars aligned for the blue half of Manchester.
On 20 minutes, the hard-working James Milner spotted Balotelli on the edge of the box, found him with a crisp pass, and the Italian guided the ball past David de Gea and into the bottom right corner of the net.
Mario stood still and then revealed the ‘Why always me?’ t-shirt, thus creating one of the Manchester derby’s most iconic moments.
A goal to the good, there was still a long way to go.
“Me and Yaya started the game and he was roaming everywhere so I was just sweeping up as normal,” said Barry.
“Darren Fletcher was playing that day and he was one of the fittest players I’d come up against, so we knew it was going to be non-stop work all afternoon.”
United had quality all over the pitch and in Nani, they had a player at the top of his game – but he couldn’t get the better of either City full-back that day.
“Up to that stage, Nani had been unreal, creating and scoring goals, but Gael and Micah absolutely shut him out,” said Lescott. “I think he swapped wings after about half-an-hour and he was out like a light in the second-half.
"We were comfortable. We enjoyed defending and took pride in it..."
“We always believed we could win the game, but we didn’t see a big score or anything like that on the horizon. If anyone did, I'd like to see the evidence to back it up.”
City went in at the break 1-0 up and with United very much in the mix, but just a few minutes into the second-half, Balotelli was felled by Jonny Evans outside the box and referee Mark Clattenburg showed the United defender a straight red card.
Was that the turning point of the game?
“It’s hard to say because we were ahead already and had dominated the game, but I think if he hadn’t been fouled, he would have gone on and scored anyway and we’d have been 2-0 up,” opined Barry.
United dug in and still believed they could turn the situation around, but on the hour, City made the extra man pay as a terrific move saw David Silva’s reverse pass leave the overlapping Milner with plenty of time to pick out Balotelli with a low cross and Mario claimed his second of the afternoon.
Daylight, of sorts.
“After we scored the second, I thought we would go and win because we just didn’t concede three or four goals in a half, so I was confident,” said Lescott.
But there was much more to come.
On 68 minutes, Micah Richards repeated the Milner overlap and found Sergio Aguero in the six-yard box and the Argentine bundled home City’s third of the afternoon.
United had no response of any substance but instinct drove them continually forward, even though City looked like scoring with every counter-attack.
“After we went 3-0 up, I think we realised how good we could be,” said Lescott. "It was sort of a turning point in many ways."
United did pull one back on 81 minutes through Fletcher, but if they felt they’d salvaged some pride, they hadn’t reckoned on a sensational end to the game by City.
A corner was flicked on by Barry and Lescott managed to keep the ball in play at the far post and sub Edin Dzeko forced the ball home to make it 4-1 on 89 minutes.
“For my assist, I always used to go towards the back stick on corners and I just reacted to Gareth’s header which was going out, keep it in play and Edin was there to turn it in from a yard out.”
Then the mesmeric Silva added a fifth with a low shot through de Gea’s legs.
But, deep into added time, City still weren’t done and as a header fell at the feet of Silva just inside his own half, he teed up the ball before spinning and sending a sumptuous half-volley through pass into Dzeko’s path – and the prolific Bosnian made no mistake to make it 6-1.
“The pass he played for Edin sort of summed David up – to have the vision, technique and then weight it perfectly – there weren’t too many players around who could play that pass,” said Barry.
Lescott was equally impressed: “Yeah, it was definitely one of the best passes I’ve ever seen – it was unreal technique, but it didn’t surprise me because I knew what he was capable of."
The goals were celebrated wildly in the away end and on the pitch, but off it, the City players didn't rub too much salt in the wounds of the Reds.
“We didn’t get carried away afterwards and it made everyone realise we were genuine contenders, which of course we were,” said Lescott.
For England midfielder Barry, it was a first success at Old Trafford, after numerous attempts…
“I was 28 or 29 at the time and I’d never won at Old Trafford in my career so to have the first victory a 6-1 win it was pretty special,” he said.
“It was the United way to keep coming at us but I think Sir Alex said after the game that he wished they’d have maybe just accepted a 3 or 4-1 defeat rather than losing 6-1, because that’s a huge hit to take in a derby.”
And though an unused sub, Pablo Zabaleta cites the game as one of his favourite City memories.
The Argentine may have watched his right-back rival Micah Richards take man of the match honours, but he couldn’t have enjoyed his afternoon more.
“Even if I was on the bench, it was probably one of the games I enjoyed the most as a City player,” said Zaba.
“I wish I had been on the field, of course, but watching every single goal we scored from the bench, seeing our fans celebrate and seeing the faces of the Man United supporters up close – believe me, it was one of the best games you could ever watch from the bench!
The feeling after the game was the best ever – you couldn’t imagine going to Old Trafford and winning 6-1. I don’t think people will ever forget that day
We’ll leave the final word to Gareth Barry, who revealed an interesting, if not tricky footnote to the day…
“Me and Joe Hart were invited to Wayne Rooney’s birthday party later that evening and as we were celebrating in the dressing rooms afterwards we thought, ‘hmm, this could be a bit awkward!” said Barry.
“To be fair to Wayne, he called us both afterwards and said there was no hard feelings and that we were both still invited, so we went to his to celebrate. It was a strange night!
“I think that game gave everyone the belief that it could be our year. It was the perfect statement and though we probably got a bit over-confident for a time, we got there in the end.”