Defending champion Barcelona needed an equalizer from Zlatan Ibrahimovic to escape from Stuttgart with a 1-1 draw, while Michael Ciani headed Bordeaux to a 1-0 victory at Olympiakos in the first leg of the Champions League knockout round 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 equalized 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,” Barcelona coach Pep Guardiola said. “It was tough.” Stuttgart outplayed Barcelona in the first half but the visiting team came back strongly after the break. “They had the possession, we had the chances,” Stuttgart coach Christian Gross said. “It was a very intense game,” Stuttgart midfielder Sami Khedira said. “We went into the match highly motivated, playing against probably the best team in the world. We had the better chances in the first half but then we conceded the goal too early in the second.” 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. The final two Champions League first legs are Wednesday when Inter Milan coach Jose Mourinho takes on former club Chelsea at San Siro and CSKA Moscow hosts Sevilla. 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.