After winning two domestic cups last term - beating Hibs at Hampden in both - Saints had a difficult opening to the current campaign, with no wins in their first five games.
However, Callum Davidson's side appear to have turned the corner after beating Aberdeen in the league and Dundee in the Premier Sports Cup over the past week.
Ross - whose side are unbeaten in their first six league games - knows Hibs must be at their best in order to get the better of opponents who have defeated them in each of their last four meetings.
He said: "They've had a brilliant week, winning at Pittodrie, then at Dens. They are a good side. We know that from last season. Callum has a system and a style of play that his players buy into and there is a togetherness.
"But it's just one defeat for us in 12 games and that was with 10 men for half an hour so that shows we are a good team. We just need to remember why we are a good team.
"Last Saturday (against St Mirren) we fell short but in parts of that game against Dundee United on Thursday, we were back at our best and we will need that again on Sunday."
Ross is heartened by the consistency his side have shown to remain in the top four of the Premiership since the very first match of last season.
He said: "We have put ourselves in a strong position and we want to stay there. I have spoken about how we have stayed in the top four for something like 44 league games now but the nature of the league this season means that you can drop out of it quite easily as well.
"The only way to ensure we stay there is winning again. We wanted to make our home form better this season and we have started relatively well, taking seven points from nine. We want to continue that and keep picking up points at home but it will be a difficult match on Sunday."