KENNY MILLER admits Rangers are entering a crucial summer on and off the park as they attempt to regroup after a nightmare Premiership campaign.

The Light Blues crashed to a 5-1 defeat to Celtic on Saturday and are now 36 points adrift of Brendan Rodgers’ side in the top flight standings.

Boss Pedro Caixinha will be given funds to bolster his Gers ranks during the close season and significant changes are required if his side are to challenge next term.

Miller has already committed his future to the club beyond the summer and the striker knows Rangers must improve as soon as possible.

"Of course it is [frustrating],” he said. “We all know what's happened to the club over the past five years and it was always going to be...I mean we were all hopeful we could get back straight away and challenge and everything's great.

“But it's not went according to plan. So yes it is frustrating at the fact we are where we are at the moment and we are finding it tough.

“Whether it's a gulf in quality or the fact that the mental side of it is creeping in now because we are going into games knowing we have had poor results against them this year.

“To be honest, I'm not looking at Celtic and saying we need to do this and that - we need to get better. The summer is going to be crucial to us."

After seeing their Scottish Cup dreams ended by Celtic at Hampden last weekend, Rangers suffered more Old Firm heartache on home soil as the Hoops eased to a comfortable derby triumph.

Miller’s second half strike was scant consolation for the Light Blue legions as they saw their side outfought and outplayed and suffer their worst ever derby defeat at Ibrox.

But Miller is confident the supporters will stay on side with Caixinha and his players as Rangers look to bounce back from a season to forget.

He said: “That's the one thing that will never change. The fans have been outstanding throughout what has been a tough, frustrating season for everyone at the club.

“We've not hit the levels we should have been expecting to hit since day one with the draw against Hamilton here.

“We've had no level of consistency or performances. We have had maybe two or three games in a row - I think our best run has been four wins in a row.

“Listen, that's not good enough to be up there challenging for the top. So there's a lot of work to be done to be in a position for us to be better next year.

"I wouldn't think [there is only so much the fans can take] because their support has been unwavering apart from a wee spell when there were other issues involved. But it's up to us as players and staff to get a team out that they can be proud of."

Defeat to Celtic means Rangers are on course to finish third this term after they missed the chance to close the gap to Aberdeen.

It has been a dramatic campaign on and off the field at Ibrox as the Gers have had to deal with the fall-outs from the Joey Barton bust-up and Mark Warburton’s exit.

But Miller insists the headlines and controversies are no excuse for a series of poor performances in the Premiership.

He said: "I'm a footballer. I just go and train every day as hard as I can and try and go and win games of football.

“Other things are off-field stuff. Clubs deal with things like this all the time. So they are no excuses.

“As a team and as a club we have underperformed this year. To be a successful team in any league, you need to have a high level of consistency and we've not done that."