Celtic manager Ronny Deila says the best is yet to come from Tom Rogic after the Australian international put in a man-of-the-match performance in the 4-1 win over Ross County on Sunday.

The midfielder opened the scoring with a superb strike in the 38th minute as his dipping drive from 20 yards gave County 'keeper Gary Woods no chance.

Leigh Griffiths took his tally to 18 for the season with two second-half goals in two minutes and Nir Bitton headed home a fourth after Tony Dingwall had pulled one back for the hosts in Dingwall.

Socceroos star Rogic has been in fantastic form this season as his Celtic career finally takes off following an injury-hit spell which saw him sidelined at the Hoops for almost two years.

And his manager thinks the midfielder will continue to improve as he establishes himself as a first-team regular at the Glasgow giants.

"In the first half we didn't create very much but it was a brilliant goal from Tom. That was good to take with us into the break," Celtic manager Deila said.

"He's getting better and better. When I first came he was injured for almost a year. Now he has been injury free for five months and I think we have just seen the start of Tom.

"He has wonderful technique, a good understanding of the game and he's a creator. He just needs to work to get an even better physique but that will come with more games and more training. I think he's going to be very good."

It is a remarkable turnaround for Rogic, who has endured a frustrating time at Celtic since arriving from A-League side Central Coast Mariners in January 2013.

The Socceroos star suffered several injury problems before being shipped back to Australia for a loan spell with Melbourne Victory.

The 22-year-old had not started for Celtic since September 2013 before his return in August and the attacking midfielder, who is expected to start in Australia's crucial World Cup qualifier against Kyrgyzstan at Canberra Stadium on Thursday, said he was playing with a smile on his face again.

"I am enjoying my football and this season has been fantastic for me. The manager has been great as have all the coaches and I'm just enjoying being at the club," Rogic said.

"Off the back of last season this season has been really positive for me and it's going well at the moment."

Rogic, who has scored five times for Celtic this season, said his stunning strike against County rated as one of the best in his career.

"It was nice and it came at an important time of the game as well," Rogic added.

"It's tough to come up here so it was nice to score but the most important thing was the win."

The win restored Celtic's six-point advantage over Hearts at the top of the Scottish Premiership and eases the pressure on Deila, who had come in for heavy criticism following his side's 2-1 defeat to Molde on Thursday which left the Bhoys bottom of their Europa League group.

"Obviously it was important to bounce back after our midweek result. This was a great result as it's a tough place to come," the Socceroos star said.

"I think it was frustrating in midweek as we didn't perform to the level that we know we can. It's gone and done now and we knew coming here it was an opportunity to show our qualities and give the fans something to cheer about."