Jose Mourinho quashed speculation on Monday that he might leave Chelsea if they won the Champions League title they so covet, saying he had made that mistake before with Porto. "If one day I win the Champions League again I want to win the Intercontinental Cup, not leave it to another manager to win it," Mourinho said on the eve of his side's Champions League opener against Werder Bremen. In 2004, after winning the European title with unfancied Porto, the Portuguese coach was lured to Chelsea by billionaire owner Roman Abramovich with a brief to turn the side into the best in Europe. He quit Portugal, leaving Victor Fernandez to secure the world club champions trophy in Japan. On Monday a somewhat muted Mourinho also sought to play down Chelsea's chances of winning the Champions League this season, saying the quality of the opposition had improved and the London side had been drawn in the most difficult group. He said at least 10 other clubs had the ambition and the players to win the trophy. "The difference is we say we want to win it. The others may not say but they have the same ambitions," he said, reeling off a string of top signings secured by clubs such as Inter Milan, who he said had the best squad in the world, Real Madrid, Barcelona and Liverpool. His own high-profile acquisitions Andriy Shevchenko from AC Milan and Michael Ballack from Bayern Munich are testament to the London side's European aspirations. Shevchenko, who will play his 99th European club game against Werder, is the highest scorer still playing in the competition with 56 goals and Mourinho was lavish in his praise for the Ukraine striker whom he called a real team player. "He just wants the team to win and be happy. He's not worried about scoring goals or being man of the match," Mourinho said. Chelsea have been drawn in Group A with champions Barcelona, their fiercest rivals for the last two seasons, Werder Bremen and Levski Sofia. Chelsea have drawn the defending champions in the group stage for the three seasons he had been in charge, facing Porto, Liverpool and Barcelona, Mourinho pointed out. He also suggested that Werder Bremen, spearheaded by Miroslav Klose, were the toughest third seeds in the tournament. Klose, however, is suffering from a thigh injury and could miss Tuesday's game, despite taking part in Monday's training. "If he can't play tomorrow it will be a big loss...he's not easily replaceable," Bremen manager Thomas Schaaf said. Schaaf added that the Germany striker would receive treatment for the next 24 hours and a decision would be made shortly before kickoff. Chelsea's new Dutch defender Khalid Boulahrouz, signed from Hamburg, said Klose was not the only worry in a side with a reputation for attacking football. "Klose is very dangerous but they also have midfielders who can score goals," he said. Chelsea winger Arjen Robben, nursing an injured calf, did not train on Monday. England midfielder Joe Cole, who damaged knee ligaments during a pre-season tour to the U.S., took a full part in the session and could start on the bench.