Any buzz from the arrival of Juan Mata quickly wore off as Manchester United lost 2-1 at Stoke City.
Charlie Adam gave the hosts the lead with a free-kick seven minutes before half-time, his shot deflected in off Michael Carrick. But Robin van Persie made it two goals in two games since his return from injury, leveling after a through-ball from Mata.
But Adam put Stoke ahead again almost immediately, his 25-yard strike flying into the top corner.
United suffered a double injury blow, with both Jonny Evans and Phil Jones taken off, and United were ultimately made to pay for their make-shift back-line.
There was still time for Rooney to force an impressive save from Asmir Begovic in injury-time, but the hosts held on for a much-needed victory over the reigning but faltering champions.