When Manchester United signed Edinson Cavani on the final day of the summer transfer window the expectation was he simply an upgrade on Odion Ighalo. An experienced striker who could provide valuable back-up and support to the existing front three at Old Trafford.

Cavani was someone Ole Gunnar Solskjaer would trust when it comes to rotation, while the 33-year-old could also make an impact off the bench in games.

But fast forward just under three months and Cavani is now United's in-form forward. In fact he might be their only in-form forward.

Suddenly the plans for Cavani have changed. At the moment he's the focal point of United's attack, the man the front line needs to be built around.

That presents new problems for Solskjaer, however. Cavani has started only two games since March and turns 34 in February. His fitness levels and professionalism may be exemplary but this is a season that will test aching limbs and muscles like never before.

So Cavani probably needs to be managed through a demanding schedule, with United playing twice a week until at least January. Is the Uruguayan fit enough to start against West Ham on Saturday and in what has turned into a crucial Champions League tie at RB Leipzig on Tuesday? If he does begin both of those then it will be three starts in a week, which would surely mean a place back on the bench for the Manchester derby on December 12.

These are the kind of decisions Solskjaer has to consider now, as a result of Cavani's stunning impact over the past week. He played well against Istanbul Basaksehir on his first start for United, then inspired the comeback at Southampton at the weekend when coming off the bench at half-time, laying on a goal for Bruno Fernandes and scoring two of his own.

Manchester United were hit by a double Neymar sucker-punch as they lost 3-1 to Paris Saint-Germain in their crucial Champions League match on Wednesday.

It means United travel to Germany needing a point from their final group match against RB Leipzig to qualify for the last 16.

Before then, the Reds have a tricky Premier League trip to West Ham to negotiate at the weekend.

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While United missed chances against Paris Saint-Germain on Tuesday night - leading to the defeat that has left qualification on a knife-edge - Cavani wasn't to blame against his former club. In fact the closest United came to going in front was a moment of ingenuity from Cavani, floating a delicate chip over Keylor Navas and against the crossbar.

Cavani's three goals for United so far is already one more than Anthony Martial has returned this season, in what has been a disappointing campaign for the Frenchman.

Marcus Rashford has two goals in his last seven appearances for United, a penalty gift-wrapped to him by Fernandes against Istanbul Basaksehir and Wednesday's deflected effort against PSG. He has also suffered a recurrence of a shoulder injury that could sideline him this weekend, at least.

Mason Greenwood's problems this season have been well documented. He was withdrawn at half-time for Cavani at Southampton. The 19-year-old will come good again but he's scored twice in 11 appearances this season.

United's search for a goal against PSG was so pressing that Odion Ighalo was back in action for the final minute, featuring for the first time since the Carabao Cup win at Brighton at the end of September.

The increased number of substitutes in Europe allows for Ighalo to be on the bench, but he hasn't made the replacements in the Premier League for five successive games, since Cavani was part of the squad.

Now Cavani is not only a fixture in the squad, but arguably the most important forward at the club right now. Solskjaer needs a return to form for his front three from last season, but until then managing Cavani's workload is going to be key.