Bruno Fernandes instigated Lisandro Martinez's brief switch to centre forward towards the end of Manchester United's epic FA Cup tie with Arsenal.
Fernandes alerted United head coach Ruben Amorim to an issue with Martinez, who was struggling to run in the final minutes of extra time.
With United players' workload increased after Diogo Dalot's sending off in the 61st minute, the team clung on for a 1-1 draw to trigger a penalty shootout that United won 5-3.
Amorim decided to move Noussair Mazraoui from left wing back to left centre back, with Toby Collyer moved to right wing back in a 5-3-1 formation, while Joshua Zirkzee dropped into midfield as Martinez went up front. "I think it's a team effort," Amorim said. "And Martínez could not run anymore in the backline.
Read more on manchestereveningnews.co.uk