Rashford received his first start under Mourinho against Feyenoord, generating several bright moments with his energy and fearlessness.
The 18-year-old was ultimately unable to force a breakthrough, however, and was replaced by Zlatan Ibrahimovic on the hour mark.
When asked whether the Englishman deserved to retain his starting place for the clash with Watford, Scholes said: “I think he did enough last week in the Manchester derby. He gave [Man City defender Bacary] Sagna a real tough time.
“He’s got great ability to run at a player. He looked like he had a goal in him.
“I think the left-hand side and right-hand side are problems for United. I don’t think those positions are set in stone for anybody. There’s a chance there.
“I think Marcus is the best one to play in that position, especially at Watford.”
Even as an isolated figure, receiving little or no help from supporting midfielders, Rashford was able to trouble Feyenoord’s defence with his energetic, fearless style on Thursday night.
Against Watford, a side that, much like Hull City a few weeks ago, will look to remain compact and sturdy, deploying Rashford on the left hand side – with Zlatan Ibrahimovic returning to the starting XI – would bring raw aggression to the attack, pulling Watford’s back four all over the place and, in turn, leaving gaps for the big Swede.
United fans will be desperate to see the youngster continue his exceptional rise to prominence.