LEE Wallace today urged his Rangers team-mates to put the agonising Old Firm defeat behind them quickly - and redouble their efforts to win promotion back to the top flight.

Wallace was bitterly disappointed with his side's poor all-round display against Celtic in the League Cup semi-final at Hampden on Sunday.

And he confessed the 2-0 reverse the Ibrox club crashed to against their Parkhead rivals was one of the most painful of his four years as a player in Glasgow.

However, the left-back knows Kenny McDowall's players cannot afford to dwell on the harsh experience as they enter the closing stages of the 2014/15 campaign.

For the Gers have a massive Scottish Cup fifth-round tie with SPFL Championship rivals Raith Rovers looming at home this Sunday.

And, five days after that outing, they have a Friday-night league meeting with third-placed Hibs in front of the BT Sport cameras at their Govan ground.

Wallace said: "We hoped that a good performance and result in the League Cup semi-final might have kicked us on a wee bit. Sadly, it was not to be. We have had a few disappointments and setbacks this season, certainly more than we should have, and the Celtic defeat was another one.

"We have watched the game back. We are hugely disappointed to lose two soft goals which were easily preventable. We are all gutted about that.

"But the only thing we can do is dust ourselves down. We just need to go and try and give the league as good a shot as we can."

Rangers are currently 16 points behind runaway leaders Hearts in the second-tier table, and the end-of-season play-offs look like their most realistic chance of going up this term.

However, the League One champions have two games in hand after their matches against the Jambos and Cowdenbeath were abandoned and postponed respectively last month.

The Tynecastle club, too, showed their first signs of frailty in the Championship 10 days ago when they were defeated for the first time by Falkirk.

Despite the huge lead Rangers would have to claw back in order to win a third consecutive title, the eight-times capped Scotland internationalist is refusing to rule anything out.

He said: "We will just have to keep going and see what happens in the league. But we obviously have to take care of ourselves first and foremost."

Walllace played in three Old Firm matches back in the 2011/12 season - his first as a Rangers player - and netted a goal in a 3-2 triumph against Celtic at Ibrox.

Yet, several individuals in McDowall's side - Fraser Aird, Ian Black, Jon Daly, Nicky Law, Darren McGregor and Steve Simonsen - had never experienced the Glasgow derby before the weekend.

Their Light Blues team-mate believes that finally doing so will, despite the unimpressive showing and defeat, prove invaluable as they enter the business end of the season.

He said: "I think they will benefit from it. They will certainly have seen what it meant to the fans on Sunday, that is for sure.

"I think it was a good taste of the fixture for the guys who haven't played in an Old Firm game. It was a great atmosphere and a great game to play in. It is about learning from it and moving on now."

Wallace was pleased Rangers performed better in the second half against Celtic after Daly replaced Aird and they switched from a 4-1-4-1 formation to a 4-4-2.

Yet, he knows that his side will have to improve their standards in the weeks and months ahead if they hope to challenge for silverware and win promotion.

He said: "A wee bit of credit has to go to Kenny McDowall, of course. You can't accommodate for individual mistakes.

"He made that wee change at half-time to try and keep us that bit more solid, and so that we could have more of a go and get back into it in the second 45 minutes.

"We didn't do too much up the other end. But we kept out the goals in the second half and limited their chances. They had a lot of the ball in deeper areas and that was fine.

"It was a wee bit better in the second half, but that doesn't make the defeat any easier for us to take. We have to work hard to do better."

Wallace, meanwhile, has dismissed suggestions the Rangers players were rusty against Celtic after not playing a competitive fixture in over three weeks in the build-up to it.

The Scottish champions had, in stark contrast, played and won three league games during that spell - scoring seven goals and conceding none in the process.

But the Gers defender said: "I felt fine. If we could have got back into it in the second half we were all ready for extra time. The manager has had us training really hard in between times.

"We have done a bit, so physically we were all fine. We were just gutted about the goals and the performance in general."