Real, who opened their European campaign with a 4-2 win over French side Olympique Marseille, will be without England captain David Beckham, nursing a foot injury after hurting his right foot when taking a freekick in the Spanish champions' 2-0 defeat to Valencia at the weekend.

And French star Zinedine Zidane looked less than fully-fit in last weekend's 2-0 defeat at Valencia.

But defender Ivan Helguera is back after a fortnight out with a knee injury to face a side Real consider their biggest rivals in Group F.

"Porto are one of the best sides in Europe, they're playing at home and will be going all out to beat us," said Brazil World Cup star Roberto Carlos.

Real's away record so far this season has upset coach Carlos Queiroz. They have lost twice, won one and drawn one.

"I can't accept us playing better at home than away," said Queiroz.

But the UEFA Cup winners, held 1-1 at Partizan Belgrade in their opening Champions League match, fear a Real backlash.

"Real have just lost so they couldn't be more dangerous," said Porto coach Jose Mourinho. "But we'll be really motivated."

Bundesliga leaders VfB Stuttgart play host to Manchester United and Brazilian defender Marcelo Bordon will be handed the job of stopping United's in-form striker Ruud Van Nistelrooy.

"He is a super striker," said Bordon. "But I would not say he is not the best. He is in the top ten."

The match at the Gottlieb-Daimler Stadium will be policed by more than 1,000 officers. Between 2,000 and 3,000 Manchester fans are expected to travel to southern Germany for the game which UEFA class as a potential risk.

Champions League newcomers Partizan Belgrade have warned French side Marseille to expect a surprise in the other Group F match.

Partizan put out Newcastle United in the qualifying rounds, and Newcastle's tormentor Ivica Iliev says the 1-1 draw with FC Porto in their opening match has boosted confidence.

"I know who the favourites are but we have already taken a point off Porto and why should we stop there," said Iliev.

Partizan have leaked eight goals in six matches in the Serb championship, but with classy midfielder Sasa Ilic and striker Andrija Delibasevic, Partizan could cause trouble for Marseille's rearguard at the Velodrome stadium.

And coach Lothar Matthaus, who won a record 150 caps for Germany, has plenty of experience of international competition.

"We're ready to seize our chance at Marseille," said the 1990 World Cup winner.

Scotland's Rangers travel to Greek side Panathinaikos for their first European fixture since manager Alex McLeish signed a new four-year contract that will keep him at the Scottish treble winners until 2007.

Rangers made a dream start, winning their opening Group E tie against Stuttgart, while Panathinaikos were thrashed 5-0 by Manchester United.

But Rangers' Georgian striker Shota Arveladze is expecting a hostile reception in Greece.

"We know their supporters will try to intimidate us but we are used to playing in these situations and we will get on with it," he said.

In Group H, Rivaldo looks to be staying at AC Milan after he was included on their squad list to travel to Spain for their clash against Celta Vigo.

Milan announced on Friday that the 31-year-old Brazilian World Cup winner would be leaving following his inability to hold down a place in Carlo Ancelotti's side.

However, after a meeting with Rivaldo on Monday, Milan vice-president Adriano Galliani said: "Rivaldo is staying at Milan and tomorrow will leave with the squad for Vigo."

The 1995 winners Ajax of the Netherlands host Belgians FC Bruges with both clubs looking for their first win in Group H.

Ajax fell 1-0 at AC Milan and Bruges could only draw 1-1 at home to Celta Vigo in the first round of matches.

Chelsea's return to the Champions League got off to a great start with a 1-0 win at Sparta Prague thanks to William Gallas and should they claim all three points at home to Turks Besiktas they would be set fair to earn their berth in the last 16 knockout stage from Group G.

Lazio, who drew 2-2 at Empoli in Italian league action on Sunday leaving them in sixth place in the table, host Sparta Prague in the other Group G fixture.