Hat-trick hero Leigh Griffiths revealed it was a half-time team talk from manager Ronny Deila that inspired Celtic to a 3-0 win over Dundee United at Tannadice.

The league leaders struggled to create chances in a lacklustre first half which ended goalless. But after a half-time grilling from Deila, the Glasgow giants emerged from the break energised and it took Griffiths just over 90 seconds to grab the opener.

The Scotland striker knocked home a second from close range in the 65th minute before completing his hat-trick from the penalty spot six minutes from time after Gary Mackay-Steven was brought down by John Rankin.

"I think the first half was disappointing," Griffiths said.

"The gaffer (Deila) gave us a good rollicking at half-time, but we came out and showed what we are all about in the second half."

It was a second hat-trick within 11 days for Griffiths, who also bagged a treble in the 4-1 win over Kilmarnock on April 15.

"That is what I do. If I play games I will score goals; I have said that all along," the striker added.

"I was just waiting for the manager to give me a good run in the team and thankfully it has now paid off.

"I have been working a lot harder in training and in the gym.

"John Guidetti came in and was flying, but I just waited for my chance and as soon as I got it I took it with both hands."

The striker's performance also drew plaudits from his manager, who praised his contribution to the side.

"He's delivered and that's what you need to do to get on the pitch and show everyone that you are good enough," Deila said of Griffiths, who initially found it difficult to break into the side when the Norwegian took charge of Celtic in the summer.

"Now his contribution is at the top level.

"He worked very hard from the start to the end. He got three goals and he was vital for us.

"He is important for the team. He is a very good finisher and works hard for the team. He wins challenges and he can link up well so he is a good player."

Celtic are eight points clear of Aberdeen, who won 2-1 away at Celtic's Cup conquerors Inverness on Saturday, with just four matches remaining.

If Celtic defeat Dundee on Friday, Aberdeen cannot afford to drop a point to United the following day to keep the Scottish Premiership title race alive

Manager Deila is keen to wrap the title up as soon as possible after admitting some of his players are tired after a long season that began last summer with the Champions League qualifiers.

"It has been a long season, especially for the players who haven't played 60 or 70 games a year before," the Celtic boss said.

"This is good learning for everyone and it's good that we have a good squad

"I want to win it as quickly as possible. I hope we get a full Celtic Park on Friday.

"The fans just now are so good. They stay behind the team the whole time.

"They understand that the players are getting a bit tired today but they stayed and gave them the energy they needed. We will need that as well on Friday.

"We are close now. We just need to carry on and beat Dundee on Friday and anything can happen."