Celtic manager Ronny Deila refused to blame the match officials for his side's defeat to Dundee United and instead demanded his side sharpen up both in defence and in front of goal.
Dundee United ended Celtic's eight-match winning run with a 2-1 victory over the Scottish Premiership leaders at Tannadice.
Celtic boss Ronny Deila has praised Dundee United for maintaining their standards despite selling their star players.
Dundee United will be without the suspended Paul Paton for the visit of Celtic on Sunday after the midfielder's appeal against a spitting charge was rejected.
Dundee United's Paul Paton and Queen of the South's Andrew Dowie have been banned for two games by the Scottish Football Association.
Dundee United midfielder Paul Paton has been charged by the SFA with spitting at an opponent during their 2-0 defeat to Aberdeen on Saturday.
Aberdeen manager Derek McInnes was understandably delighted with his side after they won 2-0 at Tannadice Park to hand Dundee United their first home defeat of the season.
Adam Rooney scored twice as high-flying Dundee United suffered a rare home defeat, losing 2-0 to Aberdeen at Tannadice.