WHEN clubs go through a transitional period the changes can be dramatic, or they can be phased in so gradually that one chapter fades into a new one.

Celtic won the league easily last season and are doing so again, but it was manager Neil Lennon who two weeks ago described his team as being in transition. In the course of the latest victory at Tynecastle Celtic used seven players who were not at the club last season.

Even the dogs on the street know Virgil van Dijk has been by far the most successful signing they made last year. The three substitutes - Teemu Pukki, Amido Balde and Derk Boerrigter - have been a collectively unimpressive supporting cast so far. Nir Biton is a work in progress who shows promise. The two main January additions, Leigh Griffiths and Stefan Johansen, already look as though they will be major components in the team next season and beyond.

What a goal Griffiths scored to break Hearts', well, hearts. Him of all people: ex-Hibernian man and goader of Jambos. Anthony Stokes showed nice footwork to wriggle himself clear of two Hearts men but Celtic's second-half opener was all Griffiths: he took his team-mate's long ball and shrugged off one defender before turning Danny Wilson inside out and rifling a low left-foot shot towards the far corner. Griffiths then celebrated in front of the fans - the Hearts fans - and hared off across the pitch to hug Lennon as derision poured down from the home stands.

When he was later substituted they taunted him about the 5-1 cup final as he walked towards the touchline and Griffiths briefly waved his hands as if conducting them, Graham Roberts-style. Lennon quickly hauled him towards the dug-out. Griffiths will give Celtic devilment, unpredictability and verve.

Johansen is like a three-quarter player so far. He does everything reasonably well, he is tidy and busy and energetic, and he also gives the impression he has more to offer. Biton looked ungainly at first - a bit too tall, a bit too skinny - but he plays with a poise and his contribution has improved. "It's taken me a couple of months to adapt to Scottish football," he said. "But I told everyone when I came here that I just need to settle in because it's a little bit different from what I'm used to in Israel.

"In Scotland there is a faster tempo. When you get the ball you immediately get pressed by two or three people. In Israel you have much more time with the ball to look around and make the right pass. Here you just don't have that.

"When we played in Turkey in the Antalya Cup [in January] we played Galatasaray who were in the last 16 of the Champions League and they gave us a lot of space to move the ball. And then you come to Hearts and they don't give you that space. But except for the weather, everything is good in Scotland. I think a lot of the players at Celtic are very good guys, they helped me on and off the pitch. It's a big honour for me to play under this coach [Lennon] because he played in my position and all the time he gives me advice and tells me what to do and what not to do. Scott Brown jokes all the time. It's brilliant being with him in the dressing room. He's a brilliant captain. All the time, he speaks. When he needs to joke, he jokes. When he needs to shout, he shouts. Broony's jokes and shouts: I've been on the receiving end of both."

Biton's complaint about not getting enough time at Tynecastle should amuse team-mates such as Kris Commons, Stokes and Griffiths. The Israeli played at the base of Celtic's midfield diamond and, comparatively, he had all the time in the world to look around and pick his passes. Ahead of him Hearts defended in depth and they successfully choked the Celtic attack for almost an hour. Commons in particular was suffocated. But the long ball to Griffiths caught out Hearts at last and another counter-attack delivered the second goal in stoppage time. Biton shoved over Jason Holt at the start of the move but nothing was given and when Balde was too strong for Jamie Hamill he squared the ball for Pukki to place only his fifth goal of the season.

"When we got behind the ball we made it hard for them and defended well," said Hearts midfielder Sam Nicholson. "It was a wee bit gutting for us to lose. We didn't want any of them to score, but Leigh Griffiths scoring is a wee bit hurtful. The improvements are there and that's all the manager really wants. We're a young side."

Any defeat stings but this one was respectable for Hearts, considering that the last time Celtic came to Tynecastle they put seven past them in the William Hill Scottish Cup. The potential saviour, Ann Budge, watched it all from her usual place in the Wheatfield Stand, attracting more fuss and attention than she ever had in decades following her team. Hearts are at Motherwell on Saturday. For the champions, their quietly evolving team takes on Aberdeen at Pittodrie tomorrow night.