Paul Scholes believes Angel Di Maria's sending off in the FA Cup defeat to Arsenal was the turning point in Manchester United's season.
The Argentinean international was given the marching orders in the second half during the 2-1 defeat to the Gunners at Old Trafford. His suspension forced Louis van Gaal to field Juan Mata on the right side of the midfield, while Ashley Young kept his place on the left wing.
Following the defeat at the hands of the north London club, the 20-time English champions went on to win four consecutive matches to extend their unbeaten record in the league to six matches.
The recent winning streak includes victories over Tottenham Hotspur, Liverpool and Manchester City in a dominating fashion. The former United midfielder admitted that he was surprised to see a change in fortunes of Van Gaal's side.
"When I look back on the key changes, I still feel that Angel Di Maria's red card against Arsenal was critical in allowing Van Gaal to build this new-look team," Scholes told the Evening Standard.
"When I look at the side it seems to me to be a triumph of the underdog - Juan Mata, Marouane Fellaini, Ashley Young. All of whom looked like they could be out the picture at the start of the season and are now having a big impact."
"I have been critical of my old club Manchester United under Louis Van Gaal this season and I have to say that I did not see this change in fortune coming. To the extent that when they go to Chelsea on Saturday, I think they have a good chance of winning the game," he said.
Mata has been impressive for United in the last four matches as the Spaniard has scored three goals and registered one assist. Scholes has heaped praise on the former Chelsea star for his brilliant performances in recent times.
"For all the attention after the derby win over Manchester City on Fellaini and Young, a lot of the credit has to go to Mata. He has given United such composure," the Old Trafford favourite explained.
"He is not a winger, in the conventional sense, but he comes inside and gets involved in the game. He always passes to a red shirt and he is so cool, as you saw with his finish against City," Scholes concluded.
Van Gaal will take his men to Stamford Bridge as United take on league leaders Chelsea on 18 April.