Jose Mourinho makes an emotional return to Porto on Wedsday (AEST) and, not for the first time this season, he will seek some UEFA Champions League solace to make up for Chelsea's patchy Premier League form.
Mourinho famously led Porto to Champions League glory in 2004 before moving to Stamford Bridge for his first stint in west London.
After reaffirming his standing as one the world's best coaches during spells at Inter and Real Madrid, Mourinho returned to Chelsea in 2013, and won the Premier League title comfortably last season.
But Mourinho has endured a miserable start to 2014-2015 domestically, with the weekend's 2-2 draw at Newcastle United leaving Chelsea with just eight points from seven league games.
Mourinho described Chelsea's first-half showing at St James' Park as "minus one out of 10", and he will be desperate for his side to show its quality in Wednesday's trip to Estadio do Dragao.
One plus for Chelsea - which routed Maccabi Tel Aviv 4-0 in its Group G opener - is that Diego Costa will be available for selection Mourinho citing the Spain striker's absence through a domestic suspension as a key reason for its sluggish performance at Newcastle.
Porto is also out to impress having failed to hit top form in Saturday's (AEST) 2-2 Primeira Liga draw against Moreirense.
Julen Lopetegui's side, which is unbeaten in the league this season, twice let a lead slip as it failed to build on the 1-0 victory over rival Benfica in its previous fixture.
Porto missed the opportunity to win in its opening group match as a late Vitaliy Buyalsky earned Dynamo Kiev a 2-2 draw after Vincent Aboubakar's double had put Porto ahead.
Lopetegui may have to cope without Yacine Brahimi for Wednesday's clash, with the winger struggling with a knee injury.
As well as Mourinho's return, there are several other acquaintances that will be renewed this week.
Porto goalkeeper Iker Casillas endured a difficult relationship under Mourinho's stewardship at Real Madrid, while Chelsea striker Radamel Falcao also returns to a club where he scored 41 league goals in 51 appearances before moving on to Atletico Madrid in August 2011.