European football's big reputations counted for nothing on Wednesday as Real Madrid, AC Milan, Manchester City and Arsenal all lost in the Champions League, while Paris Saint-Germain cruised to a comfortable 2-0 win away to Dinamo Zagreb.
Nine-time European champion Real Madrid lost 2-1 at Borussia Dortmund; seven-time champion Milan's woeful season continued with a 1-0 loss at Malaga; City blew a 1-0 lead on the way to a 3-1 loss at Ajax; and Arsenal was humbled in a 2-0 home loss to German club Schalke.
"I prepared the players badly for this game," City manager Roberto Mancini said. "This defeat is my fault."
The day after Manchester United scraped together a 3-2 win at home to Braga, the erratic form of Premier League teams was again thrust into the spotlight as City conceded sloppy goals, while Arsenal's misfiring forwards were given a lesson in clinical finishing by Schalke.
Defender Marcel Schmelzer scored Dortmund's winner to extend Madrid's terrible record in Germany. The Spanish side has lost 17 of 24 games in Germany against a German opponent -- and the only win was a 3-2 victory at Bayer Leverkusen in 2000.
Dortmund tops Group D with seven points, one more than Madrid. Ajax has three points, while City has one and is in real danger of a second consecutive group-stage exit.
"We were able to play our own game," Ajax coach Frank de Boer said. "With our wingbacks we were dominant, and they couldn't find an answer for that."
Before the match, police riding horses dispersed numerous fans as they were about to fight and 25 people were detained.
The German visitors had wasted a string of good openings by the time Huntelaar put them in front with a low drive in the 76th minute, his ninth goal of the season for club and country.
Afellay clinched victory for Schalke in the 86th, slotting home from close range after Jefferson Farfan had evaded Arsenal's defense again down the right.
The loss ended Arsenal's perfect start to the competition and leaves manager Arsene Wenger with some worrying problems after being outclassed in every department.
Schalke is on seven points -- one ahead of Arsenal.
Milan, which lost its past two Serie A matches to drop to 15th place in the standings, got one reprieve but not a second as Joaquin Sanchez made up for a penalty miss by scoring the second-half winner. The Spanish side is in control of Group C with nine points.
"Nobody imagined this. We didn't know what would happen each morning and look at what's happening now," Joaquin said. "I think all of Malaga made history today. Milan's not in its best moment but it's still a top club."
Milan is still in a decent position to qualify as it has four points, one more than Zenit St. Petersburg, which beat Anderlecht 1-0 at home thanks to Alexander Kerzhakov's second-half penalty -- his 200th career goal. Anderlecht is last with one point.
American defender Oguchi Onyewu made his debut for Malaga when he entered in the third minute of second-half injury time in the win over AC Milan. Onyewu was with Milan from the start of the 2009-10 season until January 2011, but made just one competitive appearance for the Italian club.
Greece striker Kostas Mitroglou scored the winner as Olympiakos came from behind to beat the struggling French champions.
Gaetan Charbonnier's first Champions League goal was not enough as Greece defender Vassilis Torosidis equalized in the 73rd and Mitroglou struck in stoppage time.
"For us, these three points are like gold. They are a huge confidence boost," Olympiakos midfielder Giannis Maniatis said. "They will revive our European campaign."
In Group A, Porto had trouble beating Dynamo Kiev 3-2.
Porto led 2-1 at halftime thanks to goals from Silvestre Varela and striker Jackson Martinez, either side of an equalizer from Oleg Gusev.
Nigeria striker Ideye Brown made it 2-2, but a late winner from Martinez kept Porto top of Group A with a maximum nine points -- three ahead of PSG, which lost 1-0 away to Porto three weeks ago for its only defeat so far this season.
"We made some stupid mistakes and conceded two goals," Dinamo defender Domagoj Vida said. "PSG showed its class and used its opportunities."
Dynamo has three points, while Dinamo -- which conceded a tournament record amount of goals last season -- has none after losing its ninth straight Champions League match.
French reports before the match said about 70 PSG fans had been intercepted on the border between Croatia and Slovenia in hire cars they had rented from Italy.
French police had provided Slovenian border officials with files on several hundred known hooligans from PSG, with about 150 expected to be traveling to Zagreb without tickets.
Information from Press Association and The Associated Press was used in this report.