The Scottish Premiership side routed their Dutch hosts Willem II 4-0 to move within one game of a third successive group stage campaign.
However, Gerrard urged caution against the Turkish visitors in next Thursday's one-off tie in an empty stadium.
"They are certainly coming to Ibrox as favourites, for sure," he said.
"We will certainly take confidence from tonight and tap into our results from the last couple of years. But, let's have it right, Galatasaray are a big club, a massive team. It is very frustrating, obviously, not to have our full house and that atmosphere behind us, that would give us some kind of advantage. But I think it is going to be a really tough game without that there."