Juventus, Bayern and Ajax advance

Former European champions Juventus, Bayern Munich and Ajax Amsterdam all qualified for the last 16 of the Champions League on Tuesday but Manchester United stumbled again and are not sure of their place yet.

Seven of the last 16 are now known with Arsenal, Barcelona, Olympique Lyon and Real Madrid all through before the start of Matchday 5.

United, however, in their first European game since the departure of captain Roy Keane after 12 years and nearly 500 games, failed to score in the Champions League for the seventh time in eight matches as they drew 0-0 at home to Villarreal.

Their place in the last 16 is now in the balance but their cause was helped when Lille drew 0-0 with Benfica, which was disappointing for a 76,079 crowd at the Stade de France in Paris -- a record to watch a French team in European competition.

Two points separate all four teams in Group D and a draw in United's last match against Benfica in Lisbon in two weeks could still be enough to see them through, but far from certain. It is 10 years since they failed to qualify from the group stages.

CHAMPIONS SUCCESS

Elsewhere, other former champions enjoyed more success.

Bayern Munich crushed Rapid Vienna 4-0 at home with Dutchman Roy Makaay scoring twice to ensure they would finish either first or second in Group A along with Juventus.

The Italian champions beat Club Bruges 1-0 at home with a late goal from Alessandro Del Piero to make sure of their place in the last 16 but, in stark contrast to Paris, just 9,623 fans turned up at the Delle Alpi to watch the game.

Despite the defeat, Bruges will finish third in the group and go into the UEFA Cup while Rapid, who have lost all five matches to date, are eliminated from Europe.

Arsenal had already qualified from Group B before Tuesday's win over Thun but clinched top spot after beating the Swiss outsiders 1-0 with a late Robert Pires penalty which meant they had scored in each of their last 21 Champions League matches.

Thun played most of the match with 10 men after defender Armand Deumi was sent off for bringing down Robin van Persie after 35 minutes.

Ajax, playing their 150th match in Europe's premier club competition, celebrated by making sure they would advance with Arsenal after a 2-1 home win over Sparta Prague, who have now played 13 Champions League matches since their last win.

All three goals came in the last 22 minutes of the match with substitute Nigel de Jong emerging as Ajax's hero on the night with both their goals.

Sparta skipper Martin Petras pulled one back for his side in the final minute but Ajax held on for the points.

RONALDINHO OUTSTANDING

Barcelona, who had already qualified, made sure they would advance as winners of Group C with a 3-1 win over Werder Bremen, highlighted by another outstanding display from Ronaldinho.

The Brazilian, who master-minded Barca's 3-0 win over Real Madrid at the weekend, made a goal apiece for Gabri and Henrik Larsson -- and also scored one himself in the victory.

Bremen's miserable night was completed when Miroslav Klose, the top scorer in the Bundesliga with 14 goals this season, went off with a broken bone in his face after a challenge with Rafael Marquez and now faces surgery and three weeks out injured.

Despite the defeat, though, Werder are still in with a chance of qualifying although Udinese have a better one.

The Italians came from behind to win 2-1 at Panathinaikos, moving up from bottom of the section to second on seven points.

If they can hold Barca to a draw in their last match at home on December 7 they will accompany them into the last 16.

Matchday 5 continues on Wednesday with games in Groups E-H where European champions Liverpool, Inter Milan, PSV Eindhoven and Chelsea all have a chance to qualify for the first knockout round.