Wolverhampton, England – He wasn't managing from the goal advantage to fall to Wolverhampton, 1.
O'Neill was announced as the new Sunderland manager on Saturday but will not officially take over the first team duties until Monday, leaving Eric Black to manage the Black Cats at Molineux.
Sunderland had jumped out to a second-half lead thanks to a counterattack capped off by Kieran Richardson in the 52nd minute, and looked likely to extend that lead in the 73rd minute after Sebastian Larsson was fouled in the box, but the ensuing spot kick was saved by Wayne Hennessey.
Wolves immediately responded to the Welsh keeper's save, as they countered and equalized through a Steven Fletcher header.
Fletcher netted the game-winner eight minutes later despite a questionable hand ball from Jamie O'Hara in the build up. It was not called by the referee, and Wolves claimed all three points to improve to 14 points on the season.
O'Neill will have his work cut out for him, as he will look to help the Black Cats rebound from its two consecutive losses in Premier League play. Sunderland is winless in its last eight league matches and sits fourth from bottom with just 11 points.
Stoke City 1, Everton 0
Liverpool, England - With a 1-0 win over Everton at Goodison Park on Sunday, Stoke City's recent disappointing form looks to be a thing of the past.
After losing four-straight in Premier League play, the Potters have won two on the bounce with Sunday's road win the latest reason for optimism around the club.
Defender Robert Huth notched his first goal of the season at a crucial time, as the former Chelsea man scored the lone goal of the game in the 15th minute from a corner kick.
Stoke moves into eighth place in the Premier League with 18 points, jumping ahead of tenth-place Everton on 16 points.