Wayne Rooney blamed the concession of "silly goals" for the loss of two points in Manchester United's 3-3 draw at Newcastle United on Tuesday evening.
United captain Rooney scored twice as Louis van Gaal's side led 2-0 and 3-2 at St James' Park, but they were pegged back by Georginio Wijnaldum and Aleksandar Mitrovic before a late Paul Dummett leveller.
And Rooney targeted an improvement at the back when United, who have conceded 10 goals in their last six league games, visit Liverpool on Sunday.
"I think after going 2-0 up we were in control of the game, and then we've let them back into it," Rooney told MUTV. "To then get our third goal and concede again was disappointing from us.
"I think they were silly goals to concede on our behalf and they were avoidable. They have cost us two points so we're disappointed.
"We can't keep going on conceding three goals every game so we have to work on that and create the chances without giving goals away.
"You can score as many goals as you want, but if you keep conceding goals then it's a problem. We have to keep trying to get that balance right and keep creating chances, scoring goals and keeping them out."
But Rooney was pleased that Van Gaal's team, who had been criticised for not scoring enough, managed three goals in a match for the first time since October.
"I think we're always trying to create chances," he added. "Obviously we know that's our aim, that's what we work on every day at the training ground. Sometimes it's difficult but on nights like tonight we did it so we need to keep working and keep trying to improve."
Van Gaal insisted United had only themselves to blame after twice squandering leads against Newcastle, telling reporters: "I am very disappointed, but we have to blame ourselves because we could have finished this match much earlier.
"There were big chances for [Jesse] Lingard and [Marouane] Fellaini and we didn't do that. I have said that also to my players."