It capped a remarkable 2019 for the Manchester City winger, who, two months on from reaching the summit of the English game, is celebrating his country’s second African Cup of Nations title.
Though it was Mahrez, the captain and jewel in the crown of this generation of Algerian players, who triumphantly lifted the trophy aloft, it was Baghdad Bounedjah’s freak goal which ended their 29-year wait for continental glory.
It came as early as the second minute.
Cutting in from the left, the striker’s 20-yard effort deflected off the outstretched Salif Sane’s leg and, looping over the goalkeeper’s head, dropped just in time to cross the line.
So fortuitous was it spectators could have been forgiven for thinking it was Algeria’s game to lose and so it transpired, with Lady Luck on the Desert Foxes' side again in the second half.
Senegal were handed a lifeline when the ball hit Adlène Guedioura’s hand in the area and Néant Alioum pointed to the spot, but the referee consulted VAR and overturned his decision after seeing the Nottingham Forest midfielder's arm was by his side.
It was enough for the team widely regarded as the best and most entertaining in the tournament to finish as champions, though this was far from their finest performance.
Having taken the lead, Algeria were content to let Senegal have the ball.
The Lions of Teranga enjoyed 59% of possession, but they lacked the creativity and guile needed to penetrate their opponent's defensive line and rarely produced clear cut chances.
They did go close twice, however.
M'baye Niang’s 25-yard volley flew inches over the bar in the first half, while just after the hour mark the same player was forced wide after rounding the keeper and blazed past the wrong side of the post.
Algeria almost doubled their lead on a rare foray forward, again via a slice of luck, as the ball bounced onto the top of net after Youcef Belaili's cross deflected off Idrissa Gueye, but while Senegal remained the protagonists in the final 10 minutes, they failed to truly test their opponents.
Ismaila Sarr might have done better with a volley he sent over the bar and that was a close as they came, with the Algerian defence remaining resolute to seal the victory and spark jubilant celebrations.
Everyone at Manchester City congratulates Riyad on his latest success.