Real Madrid and Barcelona will be looking for success in Europe's premier club competition this week to bounce back from their first Spanish league defeats of the season on Saturday.
Primera Liga champions and leaders Real are at home to Greek title holders Olympiakos Piraeus on Wednesday after a 2-1 loss at Espanyol while injury-hit Barcelona are away to Rangers following a 3-1 setback at Villareal.
Portugal midfielder Deco became Barcelona's latest casualty after tearing a thigh muscle at the Madrigal and will miss Tuesday's Group E clash in Glasgow along with Yaya Toure, Gianluca Zambrotta, Rafael Marquez and Samuel Eto'o.
In contrast, Rangers will take on the Catalan side with their tails up after a 3-0 rout of Celtic in the Old Firm derby as they relish the prospect of stretching their perfect start in the Champions League to three matches.
Holders Milan have little margin for error against Ukrainian surprise package Shakhtar Donetsk at the San Siro after a 2-1 reverse at Celtic earlier this month was compounded by a 1-0 home defeat by Empoli in Serie A on Sunday.
With Ronaldo still recovering from a thigh injury, coach Carlo Ancelotti must hope that fellow Brazilian Kaka rediscovers last season's form to get Milan's season back on track after a poor start.
Milan trail Inter by ten points in Serie A with less than a quarter of the season gone and once again, winning the Champions League appears to be their best chance of lifting a major trophy.
PRECARIOUS POSITION
Last season's losing finalists Liverpool are in a precarious position after collecting only one point from their opening two matches in Group A and a win at Besiktas would certainly boost their hopes of avoiding an early exit.
A last-gasp 2-1 win at Everton in the Merseyside derby has taken some of the pressure off Rafa Benitez but Liverpool will need to show the same kind of resilience in the cauldron of Erdal Inonu stadium in Istanbul.
Manchester United, in contrast, are enjoying a three-point cushion at the top of Group F after their opening two wins and will have one foot in the last 16 if they win at Dynamo Kiev, who are bottom with no points.
Injury-prone France striker Louis Saha has been sidelined with a recurring knee problem while Serbia centre back Nemanja Vidic is doubtful although he has been named in the squad after missing Saturday's 4-1 Premier League win at Aston Villa.
Vidic suffered a concussion in a 4-0 win over Wigan on Oct 6 but Alex Ferguson will take United to Kiev in good spirit after seeing his side score eight goals in their last two matches.
Arsenal also have a commanding lead in Group H and will be firm favourites to go through if they beat Slavia Prague at the Emirates Stadium on Tuesday.
Chelsea, aiming to continue their good run under Avram Grant, have a tricky Group B home match against Schalke 04 with a win putting either side in a good position to advance to the knockout stages of the competition.
