European champions AC Milan and the pretenders to their throne, Real Madrid and Manchester United, all enjoyed victories on the opening night of action in the Champions League on Tuesday.

Milan began their defence of the trophy they won last May with a battling 1-0 win over an impressive Ajax Amsterdam side at the San Siro with the irrepressible Filippo Inzaghi on the scoresheet again.

But the champions ended the match with 10 men following a stoppage time red card for midfield marshal Gennaro Gattuso.

Real Madrid, bidding to become European champions for an unprecedented 10th time, gave a superb attacking performance to beat Olympique Marseille 4-2 at the Bernabeu Stadium.

Ronaldo was on target twice for the Spanish side, while Roberto Carlos and Luis Figo, with a twice-taken penalty, added the others after Marseille had had the temerity to score first.

Manchester United were also in superb form, thumping Panathinaikos of Greece 5-0 at the Old Trafford -- with the first four goals all coming in the opening half.

For once, Man U's Dutch marksman Ruud Van Nistelrooy failed to score, but goals from Mikael Silvestre, Quinton Fortune, Ole Gunnar Solskjaer, Nicky Butt and Eric Djemba Djemba more than made up for that.

Big-spending Chelsea began their quest for glory with a 1-0 win at Sparta Prague, the only goal coming five minutes from time. But none of the crop of big-name strikers who arrived in the summer found the net.

Instead, defender William Gallas steered the ball home in the 85th minute to give them an important victory.

Milan, who scored just one goal in open play in the last five matches they played in the Champions League last season, had to wait until midway through the second half to open their account this time around.

The breakthrough was provided by Inzaghi after Ajax goalkeeper Bogdan Lobont had parried a shot from Ukrainian striker Andriy Shevchenko in the 67th minute.

It was his sixth goal in four matches as Milan went to the top of Group H following the 1-1 draw between Club Bruges and Celta Vigo in the same section.

Bruges finished with nine men after two sendings-off. Andres Mendoza was shown the red card after 44 minutes. Sandy Martens was sent off a minute from the end.

Juanfran gave Champions League debutants Celta Vigo the lead after 48 minutes, before Bengt Saeternes equalised for Bruges six minutes from time.

While AC Milan were carving out their slender win over Ajax, Real Madrid produced a great attacking display to see off Marseille.

Marseille scored first when Didier Drogba punished some typically sloppy defending by the home side with a 26th minute strike. But Real were level within three minutes after Roberto Carlos volleyed home a David Beckham cross.

Ronaldo then scored twice after 34 and 57 minutes before Figo added the fourth with a twice-taken penalty.

Daniel van Buyten again exposed Real's defensive frailties with an unchallenged 83rd minute header, but that was not enough to stop 70,000 Real fans going home happy.

Real went to the top of Group F following the 1-1 draw in Belgrade between Partizan and Porto.

Manchester United are now at the top of Group E after crushing Panathinaikos. Although they did not play particularly well in the opening stages, United raced to a 2-0 lead in 14 minutes with goals from Silvestre and Fortune within a minute of each other.

Solskjaer added a third after 33 minutes when Greek goalkeeper Antonis Nikopolidis allowed the Norwegian striker's shot to trickle under his body. Butt headed the fourth on 40 minutes and Djemba Djemba scored his first for United seven minutes from time.

Glasgow Rangers also picked up three points in the same group with a late victory over VfB Stuttgart at Ibrox. The German side went ahead in first half stoppage time when Kevin Kuranyi fired into an open goal after the ball rebounded off a post.

But German Christian Nerlinger (73) and Danish international Peter Lovenkrands (78) scored late goals to give Rangers victory.

Chelsea had to wait until five minutes from the end for their solitary strike from defender William Gallas and a 1-0 win at Sparta Prague in their Group G match.

But Lazio secured an impressive 2-0 win at Besiktas to take the early lead in the same group.

Lazio's first came when Jaap Stam rose unchallenged to head home a corner after 37 minutes. The second arrived when Stefano Fiore also scored with a header 13 minutes from time.

Although Chelsea made a winning start to their first Champions League campaign in three years, it was far from impressive.

Argentinian striker Hernan Crespo and French midfielder Claude Makelele both made their full debuts for the London side, but there was a lack of cohesion to begin with.

Chelsea gradually took control after the break and began to look the more likely winners as they have remained unbeaten in eight matches so far this season.

Matches in Groups A and D are being played on Wednesday.