Wigan Athletic manager Roberto Martinez has admitted that his side must become more clinical if they are to avoid relegation this season.
The Latics, who sit 18th in the Premier League table, lost 2-1 at Everton on Boxing Day.
Wigan frustrated the Toffees until the 52nd minute, when Leon Osman's deflected strike broke the deadlock.
Phil Jagielka headed home Phil Neville's whipped cross to double the lead 25 minutes later.
Arouna Kone set up a dramatic finish with a close range tap-in eight minutes from time but, despite creating a number of good chances, Wigan failed to find an equaliser.
"I'm frustrated and angry. It is a moment of the season where results are starting to be very important," said Martinez.
"We knew we were coming to a difficult place but the way we played the first half, I thought we stopped them from having any momentum. We were starting to get into a good position to get a positive result and actions in both boxes cost us.
"We will learn from it. It is not good enough just to play well in the Premier League."
Wigan have taken just one point from their last six matches.
