Holders AC Milan, beaten finalists Juventus and favourites Real Madrid will all be looking to build on their winning starts when Champions League action returns this week.
Milan, who defeated Ajax Amsterdam 1-0 at the San Siro a fortnight ago, travel to Spain to face Celta Vigo in Group H on Wednesday.
Joint top of Serie A with Juventus and AS Roma after cruising to a 3-0 win over Lecce, everything is going smoothly for Carlo Ancelotti's European champions on the pitch.
Off it, the desire of Brazil forward Rivaldo to leave the club in search of regular first-team football has dominated the club's agenda.
Group rivals Ajax should collect their first win at home to Bruges.
Real Madrid will be looking to stamp their authority on Group F by winning at UEFA Cup holders Porto.
Still seen as the team to beat despite Milan edging Juventus in last season's all-Italian final, Real will look to maintain their flying start after trouncing Olympique Marseille 4-2.
Real are likely to be without midfielder David Beckham after the England captain suffered a foot injury during Saturday's dismal 2-0 league defeat by Valencia.
Beckham's below-par performance was matched by Zinedine Zidane and Ronaldo, though the latter two are likely to find a higher gear in Portugal.
After a torrid time at the Bernabeu, Marseille face what is on paper their easiest game of the group phase, at home to Partizan Belgrade at the Stade Velodrome.
Group D leaders Juventus should notch a second win when they travel to Greece to play Olympiakos on Tuesday after opening with a 2-1 victory over Galatasaray.
Juventus striker David Trezeguet should return after missing Saturday's 2-0 win at Reggina.
The Frenchman will partner Marco Di Vaio in attack after the former Parma striker scored and impressed as he stood in for the injured Alessandro Del Piero on Saturday.
The Turin club's main opposition for top slot in the group, Real Sociedad, are away to Galatasaray.
Juve's Serie A rivals Inter Milan, whose 3-0 drubbing of Arsenal at Highbury was probably the most impressive result of the opening games, are at home to Dynamo Kiev in Group B.
Inter defender Marco Materazzi is out with a thigh strain and coach Hector Cuper likely to ask Ivan Cordoba to partner Fabio Cannavaro in central defence. Striker Christian Vieri, who missed the trip to north London, remains doubtful.
Arsenal try their luck in Russia at Lokomotiv Moscow.
Group E leaders Manchester United follow up their 5-0 demolition of Panathinaikos with a far trickier game at VfB Stuttgart, unbeaten at the top of the Bundesliga and yet to concede a domestic league goal this season.
United's old rivals Bayern Munich, top of Group A, have an easier task in prospect at Anderlecht.