Peterborough boss Darren Ferguson says the Posh will be "better suited" to Tuesday's trip to Brisbane Road and feels Leyton Orient missed an opportunity on Saturday.
Russell Slade's side were much the better of the two after falling behind on 16 minutes to an offside header from Britt Assombalonga and battled back to equalise through Moses Odubajo with 18 minutes to play.
It was the O's who had the better of the opportunities and Ferguson is confident his side will thrive away from London Road.
"The home game today was the one that slightly concerned me," admitted Ferguson. "I think the game will be far better suited for us away from home; it'll certainly be a better pitch - that's not an excuse - but I just think the game will be better suited for us.
"I said before the game if it was a tie there'd be no panic - I'm confident we'll get the job done now," added the Scot.
Despite struggling to test Posh goalkeeper Bobby Olejnik as often as they perhaps should have, Orient still enjoyed more of the ball, better territory and more chances and Ferguson believes the O's could rue their failure to take a lead from London Road.
"If I was in their camp, I'd think it was a missed opportunity, I think we've got a great chance now.
"But you have to give credit to them, they're a very good team, we knew that before today, nothing's changed. We go into Tuesday full of confidence, we're very good at one-off games, everyone's aware of that and perhaps we'll be the underdogs which suits me as well and we'll go there and try and win the game," continued Ferguson.
The former Preston North End manager felt his side were denied a clear penalty for a foul on Assombalonga, but admitted they had benefitted from some earlier fortune.
"We should have had a penalty, it was clear, Britt's been brought down," said Ferguson.
"I've seen Britt's one back; he makes a movement in the box and is brought down, but listen, apparently someone said the goal was offside as well, so you get the rub of the green."