The leaders in England, France and Spain all faltered at the weekend, sparking eager glances at league tables around Europe.
English champions Chelsea still hold a 12-point lead in the Premier League, although they were left licking their wounds after a 3-0 humiliation at lowly Middlesbrough.
In Spain, Barcelona's lead was cut to six points by Valencia, who beat them 1-0 at the Mestalla.
In France, Lyon's patchy form continued when they needed a last-minute equaliser to draw 1-1 at Racing Lens, leaving them seven points ahead of Bordeaux with a game in hand.
Following is a round-up of weekend action in the main European leagues:
ENGLAND
Chelsea fell to their second defeat of the season and equalled the worst loss of Jose Mourinho's coaching career when struggling Middlesbrough shocked them 3-0 at the Riverside.
Manchester United took advantage with a 3-1 win at Portsmouth to cut the champions' lead to 12 points.
Liverpool, with just one point from the previous 12 available, won 1-0 at Wigan Athletic to reach 48 points, six behind United with a game in hand.
Tottenham Hotspur stayed fourth with 45 points after a last-minute goal earned Sunderland a 1-1 home draw, while Arsenal also struck late to finish with the same scoreline against visitors Bolton Wanderers and move to 41.
ITALY
Juventus tightened their grip on Serie A when a late goal from Alessandro Del Piero gave them a 2-1 win at nearest challengers Inter Milan on Sunday.
The Italy striker struck an 85th-minute free kick to put Juve on 66 points, 12 ahead of AC Milan who moved up to second after a 4-1 win at Reggina with a Filippo Inzaghi hat-trick.
Inter also have 54 points while fourth-placed Fiorentina (50) lost 2-0 at Livorno allowing Roma to move within two points after a 2-0 win at Siena, their ninth successive league win.
SPAIN
Valencia sliced Barcelona's lead down to six points after beating the champions 1-0 in an intense contest at the Mestalla.
It was decided by a dreadful error from Barca keeper Victor Valdes who scuffed a pass to David Villa just before halftime, allowing the Valencia striker to lob the ball into an empty net.
Barcelona have 52 points with Valencia on 46 and Real Madrid a further point back.
Real, still reeling from a 6-1 midweek King's Cup defeat by Real Zaragoza, claimed their sixth successive league win with a 2-0 victory at Athletic Bilbao. Osasuna are fourth on 43 after a 1-1 home draw with Zaragoza.
FRANCE
Olympique Lyon's charge to a fifth successive title stuttered as they scraped a 1-1 draw at Racing Lens and Girondins Bordeaux beat visitors Stade Rennes 2-0.
Sylvain Wiltord saved Lyon from a second league defeat this season with an injury-time equaliser after Jussie had put Lens ahead.
Lyon have 56 points from 25 games, seven ahead of Bordeaux who claimed their sixth win in seven games with goals by Fernando and Vladimir Smicer. Bordeaux have played 26, though.
AJ Auxerre are six points further back in third after being held to a 1-1 draw at home to bottom team Metz.
GERMANY
Bayern Munich opened up a 10-point lead as they beat Nuremberg 2-1 after Werder Bremen lost 2-0 at home to bottom club Kaiserslautern.
Roy Makaay and Michael Ballack scored to take Bayern to 54 points, with Hamburg SV up to second on 44 after they beat Mainz 1-0.
Bremen dominated but goals by Boubacar Sanogo and Ervin Skela earned Kaiserslautern only their fourth win and moved them off the bottom and above Cologne.
