Kilmarnock are into the quarter finals of the League Cup after knocking out holders Celtic with a 1-0 victory at Rugby Park.
Marley Watkins scored the only goal of the game as the Ayrshire side completed an unlikely double over the Old Firm after their win over Rangers in their Premiership opener.
Killie have yet to concede a goal since the new season started with victories over both Glasgow sides and a 0-0 with Hearts at Tynecastle.
Celtic have won six out of the last seven League Cups, including three in a row from Brendan Rodgers’ last spell in charge, but were unable to reach the quarter finals this time around.
They made two changes from the 3-1 win over Aberdeen last week with new signing Gustaf Lagerbielke and Odin Holm brought in for David Turnbull and the injured Cameron Carter-Vickers.
Kilmarnock were unchanged with Derek McInnes naming the same eleven who drew 0-0 with Hearts at Tynecastle last week.
The first-half finished goalless and despite a couple of chances for either side it was a bit of a lacklustre first 45 minutes in Ayrshire.
After the break the game sprang to life and Marley Watkins scored the opener on the hour-mark to give Killie a lead against the holders to take into the last 30 minutes.
The Hoops brought on Turnbull and Yang as they chased an equaliser that would keep them in the cup that they have won in the previous two seasons.
Despite having most of the possession they struggled to create any real chances against a water-tight Kilmarnock defence who were yet to concede a goal this season.
Yang had a chance to get an equaliser but he was unable to get his shot on target as the minutes ticked away.
Despite seven minutes of injury time, Celtic were unable to put Kilmarnock goalkeeper Will Dennis under any real pressure as Brendan Rodgers suffered his first cup defeat in Scotland in his 25th knockout game.