A poor Manchester United performance saw them lose 3-2 at home to an impressive Athletic Bilbao side and only a last minute penalty gives them hope for the second leg.
Yet again they struggled at home against a talented Athletic outfit who had not come to Old Trafford to make up the numbers and deserved their first ever win in this country.
For most of this clash it was the Spaniards who made all the running and but for United keeper David de Gea they could well have been taking a more substantial first leg lead back to their homeland.
Athletic are a big strong team but their mobility frequently caught the sluggish Red Devils rearguard out and it was against the run of play that the home side took the lead.
Instead of making the most of this fortunate lead it was the visitor`s who continued to press and Markel Susaeta narrowly lobbed wide when clean through. But Athletic were not to be denied and deservedly levelled just before the break.
Twenty one goal scorer this season Fernando Llorente had already shown his threat earlier and the big striker made no mistake with a firm header from close range.
Little changed after the break with United on the defensive as the Spaniards ran midfield. And the Basques took the lead after a period of sustained pressure although television replays showed Oscar de Marcos to be marginally offside as he volleyed home.
A third goal duly arrived as hesitancy in the United defence allowed Iker Muniain to score.
With three away goals Athletic comfortably played out time as United struggled to create any chances but the home side were given a lifeline they barely deserved in injury time as Rooney scored from the penalty spot after a handball.
The final whistle was greeted with a tremendous roar from the visiting supporters who had been vociferous throughout.
Referee: Florian Meyer (GER)
Venue: Old Trafford
Man Utd scorers: Rooney 21, 90 (pen)
Athletic Bilbao scorers: Llorente 44, De Marcos 72, Muniain 90
TRIBAL ASKS: Will United have to spend in the summer if they are to improve?
Yellow cards: San Jose (ATH), Carrick (MANU)