Nicky Law admits Rangers will have to work to get in shape if boss Ally McCoist decides to stick with his new formation.
The Ibrox boss road-tested a 3-5-2 line-up during their pre-season work out and then gave the system its first competitive outing during the 2-1 extra-time win over Hibernian on Tuesday.
After starting brightly by taking the lead with Lewis Macleod's early strike, the Light Blues struggled to impose themselves during the Petrofac Training Cup first round tie.
That forced McCoist to switch back to 4-4-2 as he brought off defender Darren McGregor and replaced him with David Templeton with 23 minutes remaining of normal time.
The move paid off though as Templeton lured Leith goalscorer Danny Handling into a wild tackle that earned the striker a straight red card.
The extra man paid off for the League One champions as they eventually clinched victory with Law's extra-time strike – but the match-winner admits they are not yet comfortable with McCoist's game-plan.
He said: "It was a tough game. Hibs played really well. They put their system on the game more than we did, particularly in the second half. For 20-25 minutes we couldn't get near them.
"In the end we were just relieved to get through. There are things for us to work on and we will do. We will get better.
"We have been using this new 3-5-2 formation which we have tried out in a couple of behind-closed-doors games during pre-season. It has worked well during that spell and did again during the first half against Hibs. But after that their system dominated ours and we had to change. It is going to take time."
Rangers completed last season's League One campaign without defeat but former Motherwell midfielder Law said: "The manager said after the game that if we needed telling how hard it would be this season, we just got it there."