The hosts had taken an early lead through Kyle Walker-Peters’ seventh minute shot.
City came close to forcing a winner but had to settle for a point as our 12 match Premier League winning run was finally checked.
It was still a landmark occasion though with the draw seeing Guardiola record his 500th point as City boss - achieving the feat in the quickest time in league history - and saw us stretch our lead at the top of the table to 12 points.
City went into the game on the back of that fabulous 12-match Premier League winning run – but with Guardiola warning about the threat posed by Southampton.
Within seven minutes, the manager’s words of caution had been starkly illustrated as the hosts marched into a seventh minute lead through Walker-Peters.
The Saints right back launched a strong drive at the City defence, sprinting 30 yards down the right flank before collecting an inside pass from Nathan Redmond as he galloped into the box and then despatching a fine shot with the outside of his foot past Ederson.
It was only the third first half goal conceded by City in the league this term and just the 14th overall.
And there was another scare on 23 minutes as Armando Broja had the ball in the City net after ghosting in behind our back line – but fortunately the flag was correctly up for offside.
Southampton sought to squeeze space and deny City time at every opportunity though the hosts were grateful to keeper Fraser Forster after his block prevented Jack Grealish from finding the unmarked Raheem Sterling.
City’s fluidity and patient passing began to make inroads however and Raheem Sterling was desperately close with a 35th minute curling effort after some superb footwork had opened up the Saints defence.
With City probing and stretching the game by using every inch of the pitch one felt a reply was imminent.
However, Ederson had to be alert to parry away Bednarek’s instinctive 46th minute header from Ward-Prowse’s in-swinging corner.
Danger man Broja was then denied by the post on 54 minutes after the Saints striker beat Ederson at the near post to an inviting Salisu ball, Bednarek then blazing the rebound wide.
And City’s patience was finally and deservedly rewarded when we drew level on 65 minutes through Laporte.
Forster’s knee then somehow blocked a goal bound effort from substitute Gabriel Jesus after he stole in at the back post.
It set the scene for a City cavalry charge and the woodwork came to Southampton’s rescue on 70 minutes as a brilliant 20-yard De Bruyne shot smacked back off the post.
And De Bruyne was centre stage again on 78 minutes as his surge into the box saw him checked by Romeu and Salisu prompting a long VAR check.
It did appear as though City had a strong shout for a spot kick – but the check came to nought.
And try as we might, we could not force a winner.
This was Bernardo Silva’s 22nd successive Premier League start for City – and the Portuguese midfielder was again a bundle of energy throughout.
This was De Bruyne’s 80th Premier League assist, taking him level with David Beckham and ninth in the all-time league list.
De Bruyne however has achieved that landmark in 68 fewer appearances.
Man of the match
The Spanish international was also a tower of strength at the back throughout and made one vital block to deny Armando Broja.
Pep Guardiola's verdict
"I don't need a good result even today winning the game (to know) the title race will not be over. In January no-one is champions.
"There are many games, many tough games like today and that’s all.
"Today we played to play good and tried to defend our badge and our people as best as possible and the title will always be a consequence of what we have done.
"Today was really good."
SOUTHAMPTON: Forster, Walker-Peters, Bednarek (Lyanco 72), Salisu, Perraud, Romeu, Ward-Prowse (c), Redmond (Elyounoussi 45), S Armstrong, Adams, Broja
Subs: Cabellero, Valery, Stephens, Diallo, Walcott, Long, A Armstrong
What It Means
The draw saw City stretch our lead at the top of the table to 12 points.
However, Liverpool, who travel to Crystal Palace tomorrow have two games in hand.
After what has been an intense past few months, the City squad now have a welcome break with no games scheduled for next weekend and Pep Guardiola revealing he will afford the squad some time off next week.
We return to action on Saturday, February 5 when we play host to Championship leaders Fulham in the fourth round of the FA Cup. Kick-off at the Etihad will be at 3pm.
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