Pressure is mounting on coach Claudio Ranieri as his stumbling Juventus side host nine-times European champions Real Madrid [Images] in Turin in the standout clash of Tuesday's Champions League ties.

Real are top of Group H with maximum points and Juve are also well-placed with four points from two matches although defeat would leave them vulnerable.

Two consecutive Serie A defeats have left Juventus stuck in mid-table and they are not helped by the absence of striker David Trezeguet and keeper Gianluigi Buffon with injuries.

Elsewhere on Tuesday, defending champions Manchester United [Images] and Celtic meet at Old Trafford in Group E with the Scottish side looking to end a demoralising away run in the Champions League that reads 17 defeats and one draw in 18 trips.

The top two meet in Group F when Bayern Munich host Fiorentina. Bayern hope to have Italian striker Luca Toni fit after suffering a rib injury.

In Group G, leaders Arsenal [Images] travel to Istanbul to play Fenerbahce, their first meeting with Turkish opposition since 2000 when they were beaten by Galatasaray in the UEFA [Images] Cup final in Copenhagen.