Real Madrid will rekindle unhappy memories for Bayer Leverkusen, AC Milan head to Ukraine and Chelsea aim to add to Paris St Germain's misery when the Champions League kicks off this week.
The group phase of the world's top club competition gets underway on Tuesday and Wednesday, with all 32 teams believing they have a chance of making it to February's knockout phase.
Real start their quest for a record 10th European crown in Group B after making it two wins from two games in the Primera Liga last weekend.
England captain David Beckham steered them to a 1-0 victory over promoted Numancia with a trademark free kick, though Real still showed some of last season's vulnerability.
Leverkusen, who were beaten 2-1 by Real in the 2002 Champions League final, had their minds on other things in Saturday's 2-0 loss at FSV Mainz, and paid for it.
"The players were already thinking about the game against Real and exactly what I had feared happened," said coach Klaus Augenthaler.
Porto, surprise European champions last season after beating Monaco in the final, welcome CSKA Moscow in Group H after drawing the first match of their Portuguese title defence at the weekend, 1-1 at Braga.
AC Milan, who won their sixth European title in 2003, face a long haul to Shakhtar Donetsk in Group F after a frustrating start to the Italian season last weekend.
Milan had their Brazilian goalkeeper Dida red-carded after just seven minutes and could draw only 2-2 with promoted Livorno after twice being in front.
Semi-finalists last season, Chelsea will expect to add to PSG's woes after their miserable start to the Ligue 1 season. The Paris club are still without a win after five games.
PARIS PRESSURE
Unbeaten in the Premier League after four wins and an unlucky 0-0 draw at Aston Villa on Saturday, Chelsea have the resources to exploit the struggling French side.
"We've still got some work to do because the team are tense and a long way from their true form," PSG coach Vahid said after a 1-1 draw at promoted Istres on Saturday.
"We mustn't go looking for excuses...and I hope to see a reaction against Chelsea." Chelsea's following game will be against Porto, the former club of their coach Jose Mourinho.
Two other Franco-English ties pitch Olympique Lyon against a struggling Manchester United in Group D and last season's finalists Monaco with Liverpool at Anfield in Group A.
Lyon are unbeaten in Ligue 1 this season, level on points with leaders Toulouse and buoyed by beating Stade Rennes 2-1 on Saturday with new Brazilian signing Nilmar getting both goals.
"The fact we're unbeaten is important in my opinion," said club president Jean-Michel Aulas. "It enables us to be more confident, and to show we know how to get stuck in."
United have yet to get stuck in to the Premier League, lying 10th after scraping a 2-2 stoppage time draw at Bolton Wanderers at the weekend.
One of this week's most intriguing games will be the return after four months of former Celtic idol Henrik Larsson to Parkhead -- wearing a Barcelona shirt.
The Swedish striker found the net in Barca's 2-0 win over Sevilla on Saturday, giving them six points from two games.
Liga rivals Valencia are at home to Anderlecht, Inter Milan host Werder Bremen at the San Siro and Juventus are away to Ajax Amsterdam, the club they beat on penalties in the 1996 final.
Bayern Munich travel to Maccabi Tel Aviv while Arsenal, unbeaten in a record 45 Premier League games and winners of all five games this season, host PSV Eindhoven at Highbury.
