The sides clash in the Geoffroy Guichard stadium on Saturday and Petkovic stressed his side were quickly developing a penchant for the business end of the competition.
"We are getting a real taste of the knockout rounds and having closed the group stage door, we are now ready to open another one," the 52-year old Bosnian-born coach told a news conference.
"Our feet are still on the ground of course but we are very excited at the same time and want to progress further.
"We have improved in every game and having been together for a month, we can construct a positive atmosphere from that to produce our best game of the tournament against Poland."
The Swiss opened their campaign with a 1-0 win over Albania followed by a 1-1 draw against Romania and a goalless stalemate against hosts France.
Happy with his team's tight defending, Petkovic acknowledged they needed to be sharper up front and take more long-range shots against an even more stingy Polish side, who are yet to concede a goal in Euro 2016.
"We had at least 15 chances in the three games we have played and it is obvious that we have to be more clinical in front of goal," he said.
"It's not just down to the strikers to score, everyone must pose a threat. The final ball needs to be better and we also have to try more shots from long range.
"We're up against a very good team who have given nothing away and we need to do the same. Keep possession as much as we can and be 100 percent focussed when we don't have the ball."
Defender Stefan Lichtsteiner echoed Petkovic's confidence.
"This is the big stage where you want to prove your worth and we want to make another step so that Switzerland can be even more proud of us," the 32-year old right back said.
"The performance against France was a benchmark and gives us plenty of confidence because we played very well and had a lot of possession against a top team."
(Editing by Ed Osmond)
Share
