MUNICH, Germany, Sept 20 (Reuters) - Bayern Munich will need significant improvement if they are to stage another successful run in the Champions League after their Group F opening 2-1 victory over Valencia on Wednesday. Coach Jupp Heynckes and his players were happy to banish the nightmares of losing last season's final to Chelsea in Munich but agreed their display against the Spanish team was far from their best. "There is still room for improvement for the entire team," said Heynckes after watching his players dominate the Spanish side throughout but failing to shut out the game early on. ... More...