LONDON: Defending champions Barcelona

needed an equaliser from Zlatan Ibrahimovic to escape from Stuttgart with a 1-1 stalemate, while Michael Ciani headed Bordeaux to a 1-0

win at Olympiakos in the first leg of the UEFA Champions League knockout round matches on Tuesday.

Barcelona fell behind after 25 minutes in Stuttgart, where coach Christian Gross has rejuvenated the German side with six wins in eight matches. Cacau, who scored four goals in Saturday's 5-1 Bundesliga victory at Cologne, jumped higher than Carles Puyol to meet a cross from Timo Gebhart and scored with a powerful header at the far post.

Barca almost equalised in the 40th when goalkeeper Jens Lehmann failed to hold Lionel Messi's shot but the ball hit the post. However, Ibrahimovic came up with an away goal that gives Barca a slight edge in the second leg at home. The lanky striker collected a header from Gerard Pique and, although his first shot was well blocked by Lehmann, the Swede followed up to prod the ball home. "You have to work hard, there are no easy matches at this level. It was tough," said Barcelona coach Pep Guardiola.

Ciani turned home a free-kick from Yoann Gourcuff in first half injury time to give the French champion a useful lead to take home for the second leg, the defender heading downwards to beat goalkeeper Antonis Nikopolidis.

After the game, stewards pushed back groups of Olympiakos fans who threw plastic chairs at Bordeaux supporters while police moved in to separate rival fans outside Karaiskakis stadium. Last week, Manchester United won 3-2 at AC Milan, Lyon edged Real Madrid 1-0 at home, FC Porto beat Arsenal 2-1 and Bayern Munich gained a 2-1 first leg advantage over Fiorentina.

In a Europa League game on Tuesday, Benfica outplayed Hertha Berlin 4-0 to reach the last 16. Oscar Cardozo scored twice and Pablo Aimar and Javi Garcia also hit the target in a game between the Portuguese leaders and the side who is last in the Bundesliga.