Ruud van Nistelrooy's late goal for Manchester United earned them a 2-1 victory against Benfica.
The Dutch striker scored from close range with only six minutes left to earn United all three points, after Ryan Giggs earlier gave them the lead.
But it had looked like United would only draw after Simao Sabrosa's great free-kick levelled the match at 1-1.
Arsenal were also 2-1 winners, with a Robert Pires penalty handing them victory against Dutch side Ajax.
Robert Pires scores from the spot for Arsenal
Pires slotted the ball home from the spot after Jose Antonio Reyes was fouled in the area, although there wasn't much contact from goalkeeper Hans Vonk.
The Gunners had opened the scoring after only 80 seconds through Freddie Ljungberg, with Ajax's goal coming just a minute after Pires' penalty.