Paddy McNair says Manchester United's missed chances fuelled Middlesbrough's belief in causing an FA Cup upset at Old Trafford.
United were dumped out of the cup by their Championship opponents on Friday night after losing 8-7 on penalties after a 1-1 draw.
Ralf Rangnick's side squandered a great chance to take the lead early on when Cristiano Ronaldo dragged a penalty wide, though they would soon get a breakthrough via Jadon Sancho's deflected effort.
United continued to dominate proceedings but failed to get a vital second goal and paid the ultimate price when Matt Crooks poked in a leveller during the second-half.
Despite the setback United still had plenty of other opportunities to win the match, and former United defender McNair says his side grew in confidence as the chances continued to be missed.
"It was unbelievable," he told ITV Sport. "We started the first half quite slowly, and then in the second-half, I thought we played really well. I think we deserved the win overall.
"They weren't taking their chances, so every time they missed, that gave us a lift. Obviously, Ronaldo's penalty in the first-half was a big moment too.
"Of the last ten games, I think we have won eight. We are in very good form. When you come to a stadium like this, you are going to have to ride your luck at times but overall it was a great way to finish it."
