Lionel Messi scored twice but his penalty kick was saved as Barcelona opened the European Champions League with a 5-1 win over visiting Panathinaikos on Tuesday night.

Messi, the reigning FIFA player of the year, has six goals in five games for Barcelona this season after scoring 47 last season, when he led the Champions League with eight. He failed to score for Argentina during the World Cup.

David Villa, Pedro Rodriguez and Daniel Alves also had goals for Barcelona, which rallied after Sidney Govou scored for the Greek champions in the 20th minute. Alexandros Tzorvas stopped Messi's penalty kick.

Defending champion Inter Milan was held to a 2-2 tie at the Netherlands' Twente as the first round opened, and Manchester United played a 0-0 draw at Glasgow Rangers as American midfielder Maurice Edu made his Champions League debut for the Scottish club. United winger Antonio Valencia sustained a serious leg injury.

Schalke, with U.S.-eligible midfielder Jermaine Jones in the starting lineup, lost 1-0 at Lyon. Tottenham, in its Champions League debut, wasted a two-goal lead in 2-2 tie at Werder Bremen.

In other games, Valencia won 4-0 at Turkey's Buraspor; Benfica defeated visiting Hapoel Tel Aviv 2-0, and Copenhagen beat visiting Rubin Kazan of Russia 1-0.

At Barcelona, the Spanish champions rebounded from a 2-0 loss at home to Hercules in the Spanish League last weekend.

"They are unstoppable and can walk it all the way to the final," Tzorvas said. "It's hard to compare them with anyone else."

Messi tied the score in the 22nd minute, and Villa scored from Sergio Busquets' flick-on in the 33rd. Messi made it 3-1 in the 45th after an impressive buildup through the middle of the field. Tzorvas denied Messi a hat trick by saving the penalty kick in the 54th. Rodriguez tapped in the fourth goal in the 78th after Messi's shot hit the far post, and Messi fed Daniel Alves with a perfect lob pass on the game's last play.

"Things worked out well and it's always nice to start the Champions League with a victory," Rodriguez said. "We knew we had to win."

At Enschede, Wesley Sneijder tapped in a rebound in the 13th minute after goalkeeper Nikolay Mihaylov failed to hold on to Diego Milito's shot, but Theo Janssen's curling free kick beat goalkeeper Julio Cesar it in the 20th and Milito's own goal on Janssen's corner kick put Twente ahead in the 30th. Samuel Eto'o made it 2-2 in the 41st.

"A draw against Inter is a good result for us," Twente coach Michel Preud'homme said. "We could have won the match. I think we should be satisfied with the way we played today."

At Glasgow, Valencia was hurt in an innocuous second-half collision with Rangers defender Kirk Broadfoot. Valencia was taken to a hospital and may miss the rest of the season.

"It looks as though it's a dislocation and a fracture," United manager Alex Ferguson said. "He seemed to dig his toe in the turf. Unfortunately, it's a bad one."

United started forward Wayne Rooney and nine others who didn't start at Everton in the Premier League on Saturday.

At Lyon, Michel Bastos scored in the 21st minute, and the visitors played a man short after Benedikt Hoewedes was ejected in the 34th for a high tackle on Jimmy Briand.

At Bremen, a Petri Pasanen own goal in the 12th minute and a header by Peter Crouch in the 18th gave Spurs a 2-0 lead, but the German club tied it on goals by Hugo Almeida in the 43rd and Marko Marin in the 47th.

"I think we played well in the first 30 minutes and there was a little misfortune that we allowed the goal shortly before the break," new Spurs playmaker Rafael Van der Vaart said. "But we are happy that we have a point in our first match."

At Copenhagen, Dame N'Doye's 87th goal lifted the hosts. At Bursa, Valencia got goals from Tino Costa (16th minute), Aduriz (41st), Pablo Hernandez (68th) and Roberto Soldado (76th) against Buraspor, appearing in the Champions League for the first time.

At Lisbon, Benfica won its first Champions League game in five years as Luisao scored in the 21st and Oscar Cardozo in the 68th.