Riyad Mahrez has divided opinions during his time at Manchester City so far but there can be no doubt about the importance of his contribution against Bournemouth on Saturday.
With Kevin De Bruyne trudging towards the touchline with what seems to be a hamstring injury – which the Belgian subsequently claimed is not serious – it is fair to say many City fans would not have wanted to see Mahrez coming on in his place.
Yet the much-maligned winger was the man who came up with the goal that City needed to propel them back to the top of the Premier League on an ultimately satisfying day that threatened to end in frustration.
As well as losing De Bruyne during the first half, centre-back John Stones was also substituted not long after the interval, and had the visitors not broken down a stubborn Bournemouth defence, and failed to get past the excellent Artur Boruc, they would have had genuine concerns about their title chances – even if a draw would have taken them above Liverpool for 24 hours at least.
City's record-breaking title triumph was sparked by a late goal at the Vitality Stadium last season and the champions have a flawless record against Bournemouth, but the overriding emotion in the away end as the clock ticked down here was anxiety.
The Blues had done more than enough to win the game – the hosts had no shots whatsoever – but that has never stopped the footballing gods before.
In any event, City need not have worried quite so much. They were, although the scoreline does not show it, far superior to their opponents.
Similarly to midweek, when they saw off West Ham, they dominated completely. The goals may have dried up a little and that may be of concern, but they only needed one here given their absolute refusal to let the hosts attack.
And for that one goal they have one man to thank – Mahrez.
The Algerian has not hit the ground running since joining from Leicester City last summer, and given his £60 million fee – a club record – and the fact that he was ultimately the only senior signing during the entire window, the spotlight has shone brightly on him.
He, of course, missed a penalty at Anfield that could have put a different complexion on this title race, but his overall performances around that time meant it was not dwelled upon too much.
He was, in October and November, beginning to look like he was getting to grips with the team-mates who had so impressed last season. He was contributing a decent flow of goals and assists and providing dangerous in-swinging crosses from the right that added a bit of variety to his new club's game.
Yet suddenly that all dried up. City's three defeats in December put them in Liverpool's rearview mirror and Mahrez found himself out of the side.
The last time he started a Premier League game before Wednesday's disappointing outing against West Ham was December 30.
In that time, he had made barely a handful of substitute appearances and been left out of a squad altogether by Guardiola, after the winger had complained about his lack of league game time. No bad faces, Guardiola says.
Yet Mahrez's face was a happy one today; and his manager's too. They both knew how big a goal this was.
Mahrez's fans – and he has many, particularly in his homeland – point out (with some justification) that he never actually started any of the more worrying defeats to Leicester, Crystal Palace and Newcastle.
His critics, and there are many, have tired of his penchant for sizing up a defender, cutting inside on his left foot and then trying a shot or cross that comes to nothing.
In fairness to Mahrez, it takes time to adjust to a new club. In fairness to his critics, there is a high bar at City and the goals, assists and even dangerous crosses had dried up.
But, on Saturday, he was the difference-maker. When David Silva poked the ball into his path inside the box, he made no mistake.
He was not perfect after that; Guardiola ordered him into the right position on a couple of occasions, and he wasted a great chance to make it 2-0 when he blazed over from outside the area, when a better shot or a simple pass would have got the job done.
His finish itself was far from convincing. Some will say it was scruffy; some will say that doesn't matter.
Everybody at Manchester City can agree on one thing, though – it was a goal they really needed.