With a doubt over Kevin De Bruyne, Leroy Sane was expected to come into the City side for their trip to Brighton, a match in which they knew a victory would clinch the Premier League title.
Instead, he plumped for Mahrez, a man who missed a penalty in October's goalless draw at Liverpool, an effort that could have cost his team the league.
Eyebrows were raised at the Spaniard's decision but it proved a masterstroke as the Algerian shone on the south coast, netting his team's third goal in a 4-1 win.
Following previous rumours the 28-year-old could leave the Etihad, having been barely used following his £60million summer switch from Leicester, could he now become a starter in Pep's preferred XI?
To be blunt, probably not. Mahrez is an outstanding talent, capable of getting into the majority of top sides around Europe, but City still have better players.
His primary source of frustration was probably the form of Bernardo Silva. Both looked like they would be the 12th man in the squad, capable of covering numerous positions without ever having one of their own.
However, in De Bruyne's injury absence, Bernardo found a home in the midfield and by the end of the season was undroppable. His ascendency means he is all but guaranteed a starting role when the Citizens kick off their Premier League title defence at West Ham on August 10.
For Mahrez, a place on the bench beckons or, if City sign a new wideman, it could be worse. The former Le Havre winger was part of Guardiola's "rotation" policy last season, a situation that occasionally saw him miss out on a place in the squad altogether. For a player of his quality, 14 league starts seems pretty slim pickings.
So what does he do? Does the Sarcelles-born star stick it out in the unlikely hope he will somehow find a regular spot? Or does he leave in search of first-team football?
At 28, Mahrez is at the peak of his powers and it looks like his only chance of regular football will come away from the Etihad.