Ramsey says victory over Olympiakos sets them up for the big match.
He told Arsenal Player: "This has given us momentum now so hopefully we can build on these wins and take it into the next game.
"We've got Tottenham and hopefully we can get a good result at their place.
"I'm not sure (we are underdogs), I think we have great quality in the team.
"They've added a few new faces and we're aware of that, but we're confident in the way we play and hopefully we can get the right result there."