Bayern Munich are banking on Michael Ballack and Roy Makaay

London: Both aspects of the Champions League are on show this week as Bayern Munich take on Juventus in a clash of the titans while Swiss upstarts Thun continue their adventure with a trip to Ajax Amsterdam.

Ten years ago Ajax were champions of Europe while Thun were an amateur side playing in the Swiss third division. However, they meet on level terms in the Amsterdam Arena on Tuesday with the Swiss side enjoying life at the top.

They lost only to an injury-time goal at Arsenal on their Champions League debut before beating Sparta Prague last time out, while Ajax have just one point in Group B from a draw in Prague and are struggling in the Dutch league.

“It’s hard to make direct comparisons between Ajax and Sparta Prague but I do believe that if we perform at our best we can come away with at least a point,” said Thun coach Urs Schoenenberger.

Thun warmed up with a 5-1 win over St Gallen but Ajax’s trouble in front of goal was there for all to see as they struggled to a goalless home draw with Heracles Almelo.

Striker Thierry Henry has been named in Arsenal’s squad to face Sparta Prague on Tuesday after more than a month out through injury.

The return of Henry, who has not played since injuring his groin in France’s World Cup qualifying win over Ireland on September 7, will provide a major boost to a struggling side.

Arsenal are top of the group after two wins and can take further control with a win in Prague.

Arsenal have lost two and drawn one of their five Premier League games since the influential Frenchman and club captain was sidelined, including Saturday’s 1-2 loss to lowly West Bromwich Albion.

However, they have won both their Group B games in Europe against Swiss outsiders Thun and Ajax Amsterdam. Another victory on Tuesday would make them clear favourites to qualify for the Champions League knockout phase.

Juventus and Bayern already seem safe after two wins each in a predictable-looking Group A and with a draw suiting both sides, Tuesday’s Munich clash is unlikely to be a goal-fest.

Juventus are nonetheless in hot form having also won their first seven Serie A games and did beat Bayern home and away at the same stage last season.

Bayern Munich need Michael Ballack and Roy Makaay to snap out of their slow comeback syndrome in time. Their domestic form has been patchy since injury and illness knocked Makaay and Ballack out of their rhythm.

Makaay, the Dutch international striker, scored six goals in Bayern’s first three league matches but has now gone seven games without a goal since picking up a knee injury in September. Ballack started the season in swashbuckling form but he has played just two matches in five weeks after suffering an ankle injury and then coming down with flu.

Both players were out of form in Saturday’s 1-1 draw away to Schalke 04 ? a result that cost Bayern the league leadership in Germany ? and coach Felix Magath needs a big improvement for the match at the club’s new World Cup Stadium.

“We can’t expect Michael back at his old rhythm immediately,” Magath said. “But I’m glad he’s got the first game behind him and I hope he’ll be our leader against Juventus.”

The only concern for Juventus coach Fabio Capello is the fitness of Patrick Vieira, who suffered a groin injury during France’s 4-0 win over Cyprus last Wednesday and missed the Messina game.

Barcelona travel to Panathinaikos expecting to make it three wins out of three in Group C, where Udinese host new Bundesliga leaders Werder Bremen. Panathinaikos have never lost at home to a Spanish club in eight previous encounters. Four of the last five Spanish visitors, including Barcelona, failed to score.

Barcelona, on the other hand, have lost four of their last six European away games though they beat Werder Bremen 2-0 this season.

Group D leaders Manchester United are at home to Lille with Benfica visiting Villarreal. Manchester United have lost only one of their last 25 European home games at the venue.

Ronaldo out for a month

Meanwhile, Real Madrid striker Ronaldo will be out of action for a month after injuring his ankle in his side’s 3-0 Primera Liga victory over Atletico Madrid at the weekend, add reports from Madrid.

Real said that the 29-year-old Brazilian had suffered a partial ligament tear in his left ankle and would miss up to six matches including his side’s back-to-back Champions League Group F matches against Rosenborg Trondheim.

The club said that if his recovery went according to plan Ronaldo would be able to reappear in the Primera Liga match against Barcelona on November 20.