Jose Mourinho praised Manchester United's refusal to let fatigue get the better of them as they kept their top four bid on course with a 3-1 victory at Middlesbrough on Sunday.
Having lost to Chelsea in the FA Cup on Monday and beaten Rostov in the Europa League on Thursday, Mourinho had predicted his team might struggle against a Middlesbrough team fighting to avoid relegation.
United were also without star striker Zlatan Ibrahimovic, but goals from Marouane Fellaini, Jesse Lingard and Antonio Valencia sealed a victory which left Mourinho delighted.
"I applaud our attitude and desire and our way of thinking," Mourinho said.
"We don't have plan B, C, D, E, F and G - but we have M, N, O, P and S.
"It is fantastic because we manage in the same week, to go to the quarter-finals of the Europa League which is an important target for us.
"At the same time, we got these three points that keep us in the race for the fourth position so we still have two doors for Champions League football next season.
"These guys gave everything, we started the game really well, Valdes made three fantastic saves before our first goal. We controlled everything until our second goal."
Players from both teams were reportedly involved in a tunnel brawl after the full-time whistle, but Fellaini wouldn't comment when asked about the clashes.
"I didn't see. I don't know, I was in the dressing room," he said.