THE case for the defence has been compelling for Neil Lennon of late.

Having seen his back five come under heavy scrutiny after a series of below-par performances at the start of the season, the Celtic manager will surely have been quietly contented at how his side have improved in recent weeks.

Gone, it seems, are the high-profile blunders that offered comedy value for opposition supporters but only anxiety for Hoops fans.

Hearts, Dundee United, St Mirren and Inverness have all failed to breach the green barricade as Celtic have reinvigorated their title challenge and cut their arrears on Rangers to just four points in the last month.

Tomorrow, Celtic will face a huge test of their new-found defensive resolve, though they will welcome back a familiar face to bolster their ranks as their European destiny is decided against Udinese.

Almost a year has passed since Kelvin Wilson agreed to become a Celtic player but, after kicking his heels at Nottingham Forest and then suffering an Achilles injury playing for the Hoops in September, he now has a chance to really make his mark.

With Glenn Loovens and Adam Matthews already ruled out of the clash with the Serie A stars, Wilson looks set for a timely recall and former Hoops defender Tom Boyd reckons his presence will only add to the sense of stability built up by the Hoops backline.

"The only way you can answer criticism is by keeping clean sheets and Celtic have managed to do that recently," Boyd told SportTimes.

He WENT on: "They are on a good run, the forwards are scoring and the defence has been playing better. Neil has struggled to get a settled back line week-in, week-out but with the way things are going and the players he has coming back, he will be pleased.

"There will soon be more competition for places across the back four. The team is starting to change and the squad is starting to get stronger.

"Emilio Izaguirre is coming back and Kelvin is fit again as well, which is a massive boost for them. He was unfortunate to pick up an injury when he did and that has kept him out for a while."

Celtic head to Italy knowing that only victory will suffice if they are to book their place in the next round of the Europa League and continue their European advantage beyond Christmas.

They go into the final group match in high spirits and hopeful that the surge of form that has breathed fresh life into their title challenge can be replicated in the continental arena.

The Hoops have produced the brand of free-flowing, attacking football that Lennon demands in recent weeks while adding a defensive steel to ease the burden on the Parkhead forward line.

They have shown a new side to their game and Boyd, who saw Lennon's team grind out a 1-0 win over Hearts on Saturday, is pleased to see a united Celtic moving through the gears.

He said: "We all like to play good football, and Celtic have been doing that, but you will get games like Saturday where it is just about winning.

"Hearts were very well- organised, they defended well and limited Celtic to very few chances. It was always going to take a wonder goal to win the game and Victor Wanyama certainly came up with the goods.

"It keeps the run going and it keeps the pressure on Rangers as well. It is important that Celtic don't let the gap get any bigger, especially with the Old Firm game coming up."

The former Celts skipper continued: "It is games like Saturday that help you win championships. Celtic are in a decent position but they have got to make the most of every game that comes along, they can't afford to slip up."

Even if Celtic's European dreams are extinguished in the Stadio Friuli tomorrow night, Boyd is confident domestic success could be forthcoming as the Hoops attempt to stop Rangers recording a fourth successive SPL crown.

Their title aspirations appeared faint just a few weeks ago but Boyd reckons there is plenty of fight left in Lennon's side yet.

He said: "Players are hitting form at just the right time. The squad is starting to get stronger and they are doing well just now.

"You have still got the likes of Kris Commons to come in to the fold again and then you can add in the younger players, like Dylan McGeouch, that have come in and performed.

"The squad is evolving all the time and the signs are promising for Celtic. Also, there is a lot of spirit and commitment about the team just now, which is always extremely important."