Chelsea boss Jose Mourinho has set his sights on a win over his former club Porto to secure the Blues' qualification to the knockout stages of the Champions League.
Chelsea currently sit top of Group G, but a loss or even a draw against second-placed Porto in their final group match could see the reigning Premier League Champions drop to third behind Dynamo Kyiv.
"This was an important win. But with this group, I need a calculator because I don't know what will happen," Mourinho said following his side's 4-0 win over Maccabi Tel Aviv on Tuesday.
"I know if we win we finish first. I know if we lose we go into the Europa League. With a draw, I don't know.
"I prefer to think we have to win our final match and that's it."