Oxford United's coaching chief blasted the players for virtually "giving up" at half-time as they crashed to their fourth defeat in five games.

Head coach Horacio Rodriguez was angry at the way United yet again threw away a first-half lead by caving in during the second half.

And he slammed a lack of concentration for letting in opponents Grimsby just 50 seconds after the restart, which threw away all their hard work over the first 45 minutes.

Saturday's 2-1 defeat at the Kassam Stadium was a reminder that, for all their good play on the ball, the team still have massive problems keeping out goals.

Now down in 17th place in League Two, United have failed to keep a clean sheet in seven home games since Ramon Diaz and Rodriguez (pictured right) took over, and have managed just two shut-outs in 20 games since the end of October.

"We always make errors and we always pay for it," Rodriguez said.

"It looks like in every game we finish at half-time.

"In the second half we always make three or four grave errors.

"That's now three games that we have been leading in the first half and we have ended up losing in the second half.

"Grimsby's first goal was down to a lack of concentration - even though we talk about it all week long. It is the thing I ask for most in the week and is what I tell them about before they go out."

A clearly frustrated Rodriguez said it was all the more disappointing because United played some good stuff when they had the ball.

But they weren't very good when they didn't.

"We had some opportunities to score but when the other team has opportunites, we concede goals."

Asked if he had ever known a team that had such a poor second-half record, he replied: "No, but River Plate is a big, big club."