MIKAEL Lustig is set to be sidelined for up to two months following surgery on a persistent hip injury today.

But the right-back is confident his Celtic team-mates will be able to maintain their impressive unbeaten run in the SPFL Premiership in his absence.

And he is also confident the Parkhead club will still be challenging for their second successive league and cup double when he returns to action.

The Swedish internationalist has been one of the Scottish champions' most consistent performers throughout the 2013/14 campaign.

Yet the 27-year-old has been playing with a recurring hip problem and has no choice but to now go under the knife for an operation.

Despite having Adam Matthews available again, it is a setback for manager Neil Lennon as he has serious injury concerns.

He is without Derk Boerrigter (hamstring), Beram Kayal (ankle), Steven Mouyokolo (Achilles), Charlie Mulgrew (groin) and Tom Rogic (calf) at the moment.

But Lustig is already looking forward to returning to the side in the new year and playing without any complications.

"I will be out for a couple of months," said Lustig. "I hope to be able to come back fully fit and ready to help Celtic win the trophies we are challenging for."

It should perhaps be no surprise that Lustig is being forced to take an extended spell out given how much he has played.

He has been involved in all 12 of Celtic's matches in the Champions League this season: the qualifiers against Cliftonville, Elfsborg and Shakhter Karagandy as well as the Group H games.

Besides Lustig, only goalkeeper Fraser Forster and forward Georgios Samaras were involved with Neil Lennon's side in every one of their European outings this term.

Lustig was disappointed that his side only managed to win one match - they defeated Ajax 2-1 at Parkhead in October - and finished bottom of their section.

However, he has defended Celtic's displays in Europe's premier club competition against opponents AC Milan, Ajax and Barcelona.

The Scandinavian has also dismissed speculation that their performance levels will drop now they only have domestic honours to compete for this season.

Lennon's side is seven points clear of Inverness Caledonian Thistle in the Premiership table having not lost one of their first 15 games.

And they are in the fifth round of the William Hill Scottish Cup where they will play top-flight rivals Aberdeen at home in February.

Lustig is adamant the chance to repeat the double success they enjoyed last season is a huge incentive to his team-mates to maintain their high standards.

He said: "Of course we were disappointed not to go through in the Champions League.

"Playing in Europe is the best experience you can have as a professional footballer and it is disappointing that we will not be involved again this season.

"I played in the last 16 last season and, despite losing to Juventus, enjoyed the experience. It is unfortunate we were unable to repeat that success.

"Having said that, I think we all enjoyed the experiences. We got a very good victory against Ajax and at times I felt that we played well.

"We enjoyed a lot of possession and created scoring chances. Unfortunately, we didn't take them.

"We also didn't defend well enough at times. We need to be able to take chances when we have them and stop the ­opposition scoring at the other end at that level.

"I actually felt that we played better at times in the Champions League this season than we did last season when we qualified for the knockout stages.

"But, overall, I thought we played very well. There is a fine line between success and failure at that level of football.

"You need to be ruthless up front and unfortunately we weren't."

Celtic have far been more clinical in front of goal in the domestic scene than they have been in Europe.

In their games against Hearts at Tynecastle and Motherwell at Fir Park this moth in the Scottish Cup and Premiership respectively they scored a total of 12 goals.

But Lustig still believes there is more to come from Celtic, who take on Hearts at home in the league.

And he is optimistic Teemu Pukki, the Finnish striker who netted the winner in the 1-0 win over Hibs last week, can play a key role.

The 23-year-old, who signed from Bundesliga club Shalke 04 in the summer, has struggled after making a bright start to life in Scotland.

His close-range strike against Terry Butcher's team at the weekend was his first in 15 appearances for Celtic.

But Lustig stated: "Teemu got a goal in the win over Hibs at the weekend and I was pleased for him.

"Hopefully now he can grow in confidence and go on and score more between now and the end of the season.

"Despite the fact that we haven't lost a game in the league this season I honestly don't think we have played as well as we can.

"We would like to keep the run going and improve our performances. Some of results recently have been better. That is the standard we have to maintain now."