Harry Maguire praised the impact of Alejandro Garnacho and Joshua Zirkzee in Manchester United’s win over Leicester City, claiming the players knew Garnacho would bring them the spark they needed ahead of his half-time introduction.. United progressed to the fifth round of the competition with a dramatic 2-1 win at Old Trafford, sealed via a 93rd-minute winner from Maguire.. The Reds were second-best in the first half and found themselves 1-0 down at the interval after Bobby De Cordova-Reid’s opener shortly before the break.. United improved following the half-time introduction of Garnacho, who replaced debutant Patrick Dorgu. He added a much-needed spark in attack and he was heavily involved in United’s equaliser that was scored by fellow substitute Zirkzee.. Asked if he agreed that Garnacho changed the game, Maguire told ITV: “Yes, of course. I think he made a big impact; he always does that when he comes off the bench, so credit to him.. “He is ready, he is focused and we knew at half-time that he would probably add a little bit more directness and pace into the team. Josh also came on and I thought he had a big impact on the game.”. United were nothing short of shambolic in the first half, failing to register a single shot on target. It resulted in them being booed off by some supporters and Maguire admitted the Reds are struggling to identity why they are starting games so slowly.. “I don’t know,” Maguire added. “We can’t really put our finger on it, otherwise we would do. We know there is talent in the team, but at the moment we are not showing it to the best of our ability, there is no doubt about that.. “Our record at Old Trafford has been really poor and I think we lose that little bit of belief and that little bit of confidence and it shows.. “It comes across that maybe our body language is a little bit down and lethargic, but we need to win games to bring that back, and we will do that.”