Dani Ceballos scored a stoppage-time winner as Arsenal reached the FA Cup semi-finals.
Arsenal defender Shkodran Mustafi was pleased they secured a spot in the semi-finals of the FA Cup after they beat Sheffield United 2-1 on Sunday afternoon.
The Germany centre-back believes they should have scored more goals in their FA Cup clash with Blades at Bramall Lane.
Nicolas Pepe's first-half penalty broke the deadlock and seemed to be the only goal of the match, but later in the closing stages, Sead Kolasinac's poor clearance helped David McGoldrick cancel out Pepe's opener in the 87th minute.
However, substitute Dani Ceballos beat Dean Henderson with a low close-range strike from a tight angle to book a trip to Wembley for Mikel Arteta's boys.
Speaking to BT Sport after the match, Mustafi said: "Normally I think before we conceded there is the moment we have to kill the game. But we didn't and conceded. But it shows character. It helps the team to get back confidence. Today we didn't give up, even when they equalised. You have to prepare for extra-time but got rewarded.
"Sometimes you have to see what the opponent does. There were a lot of long balls. It is not always easy to find solutions. This team believes in how we want to play football and tries things even when it doesn't look as good as it should. We have to believe in the process."
On team-mate David Luiz, who has struggled with form recently: "At the end of the day we are human beings and make mistakes. As a defender life is not always easy but he is experienced enough and is a fantastic team-mate. For me, he is a big personality and I am happy to have him on the team."