European champions AC Milan crashed to a shock 1-0 home defeat by Club Bruges of Belgium on a miserable night for Italian clubs in the Champions League on Wednesday.
With Lazio losing 2-1 at Chelsea, and following Inter Milan's 3-0 loss at Lokomotiv Moscow on Tuesday, only Juventus of Serie A emerged unscathed at the halfway stage of the group phase.
In contrast it was a good night for England following Arsenal's 2-1 defeat at Dynamo Kiev on Tuesday.
Manchester United won the all-British duel against Scottish champions Rangers 1-0 at Ibrox while Chelsea impressed with an excellent second-half display against Lazio.
With three matches played and three to go, Real Madrid, 1-0 winners over Partizan Belgrade and Juventus, who beat Real Sociedad 4-2 on Tuesday, are the only clubs with a maximum haul of nine points from their games.
Only Olympiakos, beaten 1-0 at Galatasaray on Tuesday, have lost all their matches. Most of the groups are evenly poised as the group phase moves into its second stage in two weeks time.
Milan, who like their Serie A rivals Inter Milan, Juventus and Lazio came through the first two games unbeaten, were sent reeling at the San Siro by a sizzling first-half goal scored by Bruges' Peruvian forward Andres Mendoza to throw Group H wide open.
Ajax beat Celta Vigo 1-0 in the other match in the section with Zlatan Ibrahimovic scoring early in the second half.
Ajax top the group with six points, followed by Bruges (4), Milan (4) and Celta Vigo (2).
Lazio, also unbeaten in their opening two matches, went down 2-1 to Chelsea at Stamford Bridge after taking the lead in the first half of their Group G match through Simone Inzaghi.
But Chelsea, coached by Italian Claudio Ranieri, deservedly won with goals from Frank Lampard and Adrian Mutu midway through the second half after Lampard had sent a screamer for what looked like a certain goal crashing against the bar at the end of the first half.
Sparta Prague beat Besiktas of Turkey 2-1 in the other match putting Chelsea two points clear at the top on six points. Sparta have four, Lazio four and Besiktas three.
Sparta's first win in the competition put them back in contention for a place in the last 16 thanks to a late winner from Karel Poborsky.
While Chelsea were beating Lazio in London, English champions Manchester United gave their Scottish manager Alex Ferguson three welcome points with a 1-0 win over his old club Rangers in Glasgow in Group E.
Defender Phil Neville was the unlikely match-winner with a superb solo goal after only five minutes.
With VfB Stuttgart beating Panathinaikos 2-0 in the same group, Stuttgart and United now have six points, followed by Rangers on four and Panathianikos on one.
Stuttgart, unbeaten in the Bundesliga this season and 2-1 winners over United in their last match, were too strong for Panathinaikos and took the lead when Hungarian striker Imre Szabics scored with a diving header after 13 minutes.
After Croatian midfielder Zvonomir Soldo added a second in the 25th minute the contest was effectively over.