Sydney FC star Milos Ninkovic says doubts over the A-League premiers' form leading into the finals is driving his team's bid for back-to-back championships.

The Sky Blues won just one of six regular-season games after the restart before roaring back into form with a 2-0 semi-final win over Perth on Wednesday to secure a grand final date with Melbourne City.

"Everyone started talking that we are not good enough anymore - (like) we forgot (how) to play football," Ninkovic told reporters on Thursday.

"That was I think annoying for everyone - the club, the players, the coaching staff.

"But we all know that we have a very good squad, that we didn't forget (how) to play football and I think we showed that yesterday."

Ninkovic said it had been "difficult" for the Sky Blues to maintain form after securing the premiership, but he'd always been confident finals were a different ball game.

"We want to prove (a point), yes," he said.

"Everyone was saying we weren't good enough anymore, but we wanted to show that when you look at these five, six games - I need to be honest - we were not switched on. We made so many mistakes.

"But it's hard to play when you've won the premiers' plate (with) five games (to go).

"I think yesterday everyone was switched on and when we all switch on, then no-one can beat us."

The Serbian playmaker is aiming for his third grand final win from as many attempts.

Melbourne City beat Sydney 2-0 on August 1 but Ninkovic was confident the Sky Blues' finals experience would hold them in good stead on Sunday.

"The final is gonna be a different game - it's one game and it's a final," he said.

"When it comes to the finals series this team (Sydney) really, really know how to play because I think we play much better when we're under pressure."

Coach Steve Corica said the Sky Blues were driven by the opportunity to make history.

Melbourne Victory have also won four A-League championships, while Sydney City, South Melbourne, and Marconi Stallions did likewise in the NSL.

Only Brisbane Roar in 2011 and 2012 have won consecutive A-League grand finals.

"We have set our sights on going back-to-back," Corica said after Wednesday's win.

"This club wants to win trophies. Only one team in the A-League has gone back-to-back so that would be a very good achievement for the club."