Tottenham boss Andre Villas-Boas could see his team drawn with Europa League opponents Porto.
Progressing as group winners means Spurs will miss the best of the Champions League teams dropping down in to the Europa League for the knock-out stages.
But tricky ties could still be found if they are drawn against the likes of Juventus, Ajax, Lazio and Porto, with Villas-Boas not wanting to return to face his former employers.
"It is possible," he said on a potential clash with Porto.
"On a personal level I wouldn't like that. Our aim is to go all the way to the final and I wouldn't like that.
"I have tremendous gratitude to the club and I'm a great fan so hopefully that doesn't happen until the final."
