Colback rues League Cup defeat
Jack Colback believes Sunderland have cost themselves a "massive opportunity" to claim silverware by exiting the Capital One Cup on Tuesday.
Middlesbrough defeated Sunderland 1-0 at the Stadium of Light thanks to Scot McDonald's 39th-minute strike, and Colback admits he and his team-mates felt the fixture against the Championship side gave them a good chance to advance to the quarter-finals of the League Cup.
"That wasn't good enough. We didn't create enough and we have missed a massive opportunity. It's a bitter pill to swallow," Colback told the Sunderland Echo.
"We weren't good enough all over the pitch. We made mistakes we shouldn't be making. We shouldn't be nervous because we've played the game long enough now and should be able to deal with that pressure.
"We wanted to do well in this competition. We missed a big chance last season in the FA Cup and this is another missed opportunity.
"We want to play in finals and a few Premier League teams have dropped out of this cup. It was a chance. We were at home and we expected to win the game. We let down ourselves and the fans.
"And you want to win derby games. We were disappointed not to beat Newcastle and now this."
The midfielder feels Sunderland were not creative enough against their north-east rivals, suggesting confidence may be an issue with some of the players within Martin O'Neill's squad.
"We had most of the play and didn't really create any gilt-edge chances," he said.
"We are not worried about that too much because we know we have the players who can create and we believe it will come.
"Maybe confidence is a slight issue. Winning games does breed confidence and we have only had the one win in the league.
"Sometimes you can overplay a bit and maybe we try to play a pass when we should take a shot. If you don't shoot, you are never going to score.
"We are working hard, but that's not enough. We are not really performing at the moment and we do have some great players, international players in our team."