Watch Griffiths hit number 51 and a screamer from Commons

Ronny Deila saluted Leigh Griffiths for scoring the 50^th and 51^st goals of his Celtic career and slapped a priceless tag on his key striker.

Griffiths opened the scoring for Celtic in the 4-1 win at Dundee United before Jozo Simunovic added a second before the interval.

Simon Murray pulled a goal back for the home side before half time but goals from Griffiths and Kris Commons put Celtic six points clear of Aberdeen before Derek McInnes side travel to Ross County on Sunday.

“Leigh’s goals are vital for the team,” Deila said of the striker who took his total for the season to 24. “He is doing a fantastic job, he is dangerous all the time, he gets behind defenders and creates space for the others in the team.

“I couldn’t put a price on him, there is no price for Leigh, he’s not going anywhere.”

After losing at home to Motherwell before Christmas Celtic have started the new year with three wins against Partick Thistle, Stranraer and Dundee United.

The hoops are heavy odd on favourites to win their fifth consecutive title but Deila feels that his side are playing with a new freshness as they approach a crucial stage in the campaign.

“Scoring four goals away is always hard, that is a good sign and we could have got more,” the Celtic boss added.

“We played so many games before Christmas, there was games all the time but a few games were postponed which allowed us to train more and find more energy.

“It’s going to be an important few months and we’re looking in good shape.”