LONDON — Cristiano Ronaldo scored twice on his Champions League debut for Real Madrid to lead his new team to a 5-2 win at FC Zurich, while the Manchester United side he left after last season's final won its opening match 1-0 at Besiktas.
World player of the year Ronaldo scored a pair of free kicks for the record nine-time European champion, although the second was punched into the net by Johnny Leoni as the goalkeeper tried to clear it.
Former European champions AC Milan and Bayern Munich also won their first group matches, while Chelsea beat visiting FC Porto 1-0 and Juventus stuttered to a 1-1 draw with Bordeaux.
Milan won 2-1 at Marseille, Bayern Munich won 3-0 at Maccabi Haifa and Atletico Madrid was held to a 0-0 draw by debut-making Cypriot side APOEL Nicosia.
Without a European title since 2003, Madrid was 3-0 ahead at halftime in Switzerland and sealed its win with another two goals in the closing moments.
Ronaldo opened the scoring in the 27th minute with a trademark free kick past Leoni, and Raul Gonzalez made it 2-0 seven minutes later with a close-range tap in.
Gonzalo Higuain scored from a pass by Raul in first-half injury time to seemingly put the match beyond Zurich, but the debut-making side scored twice in a minute.
Xavier Margairaz hit a 64th-minute penalty following a foul on Alexandre Alphonse by goalkeeper Iker Casillas and Silvan Aegerter headed in to make it 3-2, but Ronaldo's second kick and a goal by Jose Maria (Guti) Gutierrez made the game safe.
Filipo Inzaghi, who is vying with Raul for the title of the Champions League all-time leading scorer, hit another two goals to give Milan victory at Marseille.
Inzaghi opened the scoring in the 28th minute when he beat Marseille goalkeeper Steve Mandanda from close range and, although Marseille equalized just after the interval through a header from Argentina defender Gabriel Heinze, Inzaghi scored again from a cross by Clarence Seedorf.
The win put seven-time winner Milan level with Madrid on three points in Group C.
Manchester United could have used some of Ronaldo's scoring prowess in Istanbul as it created few openings in its first tournament match since losing 2-0 to Barcelona in Rome in May.
Midfielder Paul Scholes, who was sent off in the Premier League on Saturday, headed the ball into the net from about 12 yards with 13 minutes remaining after goalkeeper Hakan Arikan pushed out a shot from Nani.
It was a slow start to the European season for United, which lost last season's final 2-0 to Barcelona.
"Being the first game, you always want to win that, but I was quite comfortable with the performance," United manager Sir Alex Ferguson insisted. "I thought they did quite well most of the time, kept good possession."
Still, United shares the Group B lead with its next opponent after Wolfsburg beat CSKA Moscow 3-1 with a hat trick by Brazilian striker Grafite.
"It was a perfect evening - first Champions League game and first victory," Wolfsburg striker Edin Dzeko said.
Wolfsburg plays at Manchester United on Sept. 30 in the next round of group matches.
Bayern took the early lead in Group A after two goals by Thomas Muller helped it to victory in Israel, with Bordeaux and Juventus next after their 1-1 draw in Turin.
Neither side was able to impose itself in rainy conditions but Vincenzo Iaquinta gave Juventus the lead in the 63rd when he linked up with captain Fabio Cannavaro.
Jaroslav Plasil equalized for Bordeaux in the 75th, scoring at the far post after Fernando had flicked on Yoann Gourcuff's free kick.
Nicolas Anelka scored the only goal in Group D when he gave Chelsea a 1-0 win over Porto.
The remaining opening eight matches are played Wednesday, with Inter Milan against Barcelona, Liverpool hosting Debrecen and Arsenal playing Standard Liege.