Chelsea are looking forward to a reunion with Michael Ballack in the UEFA Champions League, according to the club's communications director, Steve Atkins.
The 2008 finalists were drawn in Group E along with Valencia, Bayer Leverkusen and Belgian club Genk.
That means new signing Juan Mata will be facing former club Valencia after completing his move to Andre Villas-Boas' Chelsea.
The draw will also see Ballack, who left Stamford Bridge in 2010 after four years at Stamford Bridge, face his ex-employers.
Atkins said: "Every draw throws up challenges and this is no different, and I have spoken to Andre and he certainly feels that too.
"Valencia is a formidable team and a very difficult place to go with their support - Juan Mata will be returning there a little bit more quickly than he thought!
"Bayer Leverkusen is also a difficult one and we will be delighted to meet up with Michael Ballack again, and Genk too are full of talent and should not be underestimated."
Which club has the best draw in the Champions League?