Manchester United gained revenge for last year's 2-1 loss to Benfica in Lisbon that knocked it out of the UEFA Champions League at the group stage with a 1-0 win at the Estadio da Luz on Tuesday night.
United won the match on the second day of group play thanks to a stunning shot by French striker Louis Saha -- its first away win in the competition in nearly three years.
Arsenal and Lyon are the only other teams in Groups E-H with six points after two games.
The Gunners beat Porto, 2-0, at home. Alexandr Hleb and Thierry Henry scored in the night's other Anglo-Portuguese clash.
"The team has a lot of potential and is getting stronger in every game," Arsenal manager Arsene Wenger said.
Lyon, which defeated Real Madrid, 2-0, in its opening game at home, won, 3-0, at Steaua Bucharest. Brazilian forward Fred, Portuguese midfielder Tiago and young Frenchman Karim Benzema scored for the five-time defending French league champions.
Real Madrid got its first win in the Champions League campaign with a 5-1 victory over Dynamo Kiev. It was up, 3-0, at halftime on goals by Dutchman Ruud van Nistelrooy, captain Raul and Jose Antonio Reyes, and Raul and Van Nistelrooy each added another after the break.
UEFA CHAMPIONS LEAGUE
(Day 2, Tuesday)
Real Madrid 5 Dynamo Kiev 1
Steaua Bucharest 0 Lyon 3
Benfica 0 Man. Utd. 1
Celtic 1 FC Copenhagen 0
FC Porto 0 CSKA Moscow 0
Hamburg 1 Arsenal 2
AEK Athens 1 Anderlecht 1
Lille 0 AC Milan 0
In Wednesday's Champions League action, England champion Chelsea faces Levski Sofia, live on ESPN2 at 2:30 pm ET. Click here for other games on U.S. TV.