Trabzonspor, a team that failed to initially qualify for Europe's elite tournament, ripped up the Champions League formbook in style with a 1-0 win at beleaguered 2010 winners Inter Milan in their group stage debut on Wednesday.

Ondrej Celustka struck 14 minutes from time to leave Inter reeling and pile the pressure on new coach Gian Piero Gasperini after only three games in the job.

The Turkish runners-up, only in the competition after Fenerbahce were withdrawn because of match-fixing allegations, looked comfortable throughout before Celustka expertly hooked the ball in on the slide after Halil Altintop hit the bar.

Just before the goal, Inter substitute Diego Milito spurned two gilt-edged chances when his close-range effort was saved and then his header went over but generally the hosts were poor in their opening Group B clash.

Gasperini has now lost his first three matches in charge, including the Italian Super Cup defeat by AC Milan.

"We are not in a lucky moment, this defeats leaves us with lots of regrets but the team know they have given a lot and put in a decent showing," Gasperini told Sky TV.

"We are a team that will definitely get better, we have potential, will will get injured players back. The will and the determination of the players is clear. Moratti has always really supported me."

The coach has though already been criticised in the media by the club's owner Massimo Moratti, who has seen bosses Jose Mourinho, Rafa Benitez and Leonardo leave since their 2010 treble as last season went sour.

Manchester City almost paid the price for wasting chances and ignoring warnings before Aleksandar Kolarov's free kick salvaged a draw at home to fellow Champions League newcomers Napoli on Wednesday.

The English side had hit the woodwork twice and seen several shots whizz just wide before falling behind to an Edinson Cavani goal midway through the second half as Napoli lived up to their reputation as ruthless counter-attackers.

City coach Roberto Mancini blamed first-night nerves for the mistakes, which included having to call on captain Vincent Kompany to clear a Marek Hamsik shot off the line, and he was relieved to get Kolarov's 75th-minute equaliser.

"All the players wanted to win this game and to score. Instead if we played simple we would have done better," the Italian told a news conference after his side failed to match their breathtaking start to the Premier League season.

"It was maybe desire or the pressure ... Taking forward seven or eight players is just not going to work," added Mancini, whose City side are joint top of the Premier League with maximum points from their opening four games.

With Bayern Munich and Villarreal the other opponents in Group A, Napoli had been widely seen as the most straightforward opponents for the world's richest club even if they did finish third in Serie A last season.

City had hidden their nerves well with a lively start as Samir Nasri tried his luck in the third minute before Edin Dzeko used all his muscle and height to power through the Napoli defence only to send his effort just wide.

The hosts got a sharp reminder to be wary of their visitors on the break midway through the first half when forward Ezequiel Lavezzi cracked a powerful curling shot against the crossbar.

Welsh midfielder Ryan Giggs extended his own record as the Champions League oldest goalscorer with a superb strike that earned Manchester United a 1-1 draw against a lively Benfica side in their Group C opener on Wednesday.

Giggs, who will turn 38 on Nov. 29, cancelled out Oscar Cardozo's fine 24th minute goal with an equally well-taken finish three minutes before halftime for last season's beaten finalists.

"This is why Giggs is such a legend, why he has been one of United's best players for so many years," said United captain Patrice Evra.

United manager Alex Ferguson was happy enough with a point.

"All in all, it was a good European night, good to watch. I thought the two goals were terrific," he told a news conference.

"I thought our possession in the first half of the game was too cautious. Once Ryan scored we played much better."

Toni Kroos and Rafinha scored as Bayern Munich cruised to a 2-0 win at Villarreal in their opening game of Champions League Group A on Wednesday.

Franck Ribery set up Kroos to score after seven minutes and the European heavyweights, making their 250th European Cup appearance, dominated for the rest of the match.

Bayern always looked the more likely to score as Villarreal struggled to get back into the game, and substitute Rafinha sealed the result with a wonderful piece of skill to create and score the second goal in the 76th.

It was the perfect start to the group stage for Bayern who have an added incentive to reach the Champions League final this season as it is to be played at their Allianz Arena next May.

"We saw plenty of the ball but didn't create many chances," Villarreal midfielder Cani told Spanish television.

"It's only one game and we didn't expect to lose the first one but there is still a long way to go."

Real Madrid began the quest to win their 10th title in Europe's premier club competition with a 1-0 victory at Dinamo Zagreb in Champions League Group D on Wednesday.

Argentine winger Angel Di Maria scored in the 53rd minute as Real, playing in an unfamiliar all-red kit, finally beat the inspired Ivan Kelava who produced a string of fine saves in Dinamo's goal.

The only blot on the night for the Spanish team was the 73rd-minute dismissal of left back Marcelo for diving in the home penalty area. It was his second yellow card.

Dinamo, playing in the Champions League for the first time since the 1999-2000 campaign, were not overawed by Real and nearly scored in the second minute when Milan Badelj volleyed over from a corner.

Cristiano Ronaldo spurned a good chance a minute later, shooting wide of the far post from 10 metres when he had only the 6-foot-5 Kelava to beat.

Karim Benzema then twice went close for Real, his first shot from a tight angle shaving the woodwork before Kelava kept Dinamo on level terms with a brilliant double save.

The keeper parried a Di Maria effort from close range and also kept out the rebound, a volley by Mesut Ozil, with a superb reflex stop.