Colchester boss John McGreal admitted his surprise at watching teenage substitute Noah Chilvers stepping up to score the winning penalty as his side dumped Premier League Crystal Palace out of the Carabao Cup.

The U's reached round three for the first time in 15 years with a 5-4 penalty shoot-out victory followed a dull 0-0 draw at Selhurst Park.

Palace, fresh on the heels of a 2-1 win at Manchester United on Saturday, made 10 changes to their side and came closest to settling the tie in normal time when Christian Benteke's strike came back off the underside of the crossbar.

But Colchester, 75 positions below the Eagles in the football pyramid, held on to take the game to penalties – where Andros Townsend saw his first spot-kick saved by Dean Gerken.

McGreal's side tucked away all of their five penalties to seal a place in the third-round draw – even if he was caught out by 18-year-old Chilvers taking the deciding kick.

"We are big on academy products coming through," he said.

"We have a young boy coming through at right-back, Chilvers comes on, he has been training with us for a good year and has little bit of snippets of playing.

"Little did I know, I see him pick the ball up and take the fifth penalty, fair play to the lad. I know up to four but after that I let the boys figure it out. We haven't practised penalties but we have good, technical players."

McGreal is now keen to face top-flight opposition at home in the next round, with Palace manager Roy Hodgson disappointed by the performance of those players who came into his team.

"Yes that is very true," he replied when asked if the result was a come-down after the United win.

"I believe that the team we put out tonight would be capable of wining the game, it was important for some players to get a chance to show what they can do. We had injuries to Ward and Schlupp anyway and some players coming back.

"Having said all that, I still think the starting line up today in my opinion would be capable of winning the game. They didn't because we didn't play well enough and Colchester played very well.

"That is what being a professional footballer is all about. We sign players, believe in them and believe that when they get their chance they will shine.

"You can't do more than give them a chance to come in and shine and there will be some who aren't happy with their performance.

"But the bottom line is if we can't start scoring goals it will be difficult for us and that is because we don't create or take our goalscoring chances, so as a result you are never sheltered."