Leigh Griffiths grabbed a double and missed a penalty as Celtic claimed a 2-1 win over Motherwell on Saturday that extends their lead at the top of the Scottish Premiership.

The Hoops now have a massive eight-point advantage over Aberdeen, who lost 2-1 away to Hearts on Friday night, with just five games remaining as they close in on a fifth successive league title.

A dominant first-half display saw Griffiths fire a penalty wide before making amends as he steered a 44th-minute shot past Connor Ripley.

Former Celtic striker Scott McDonald had Motherwell level on the hour mark before a mistake from Ripley, who had earlier made a string of saves to deny the Glasgow giants, allowed Griffiths' shot to squirm under him in the 75th minute.

Despite the victory, Celtic first team coach John Kennedy admitted it had been a tough encounter.

"In the first half we had plenty of chances but didn't quite take them and we had to hang on a wee bit for a spell in the second half," Kennedy said.

"Whenever it's 1-0 it's always uncomfortable and then they get a goal but we showed great character to go and get a second goal and see the game out."

Motherwell will now have to rely on other results if they are to claim a spot in the top six as the league splits in two after this weekend's games.

"Celtic are the champions elect and you expect a difficult game against them so I've no complaints," Well manager Mark McGhee said.

"My team have performed heroics since I got here and if we do end up in the bottom six then we have had a good go."

Motherwell, with five wins in a row, started brightly and had the first chance of the match when Marvin Johnson's low cross found Chris Cadden but the midfielder scuffed his shot wide with the goal gaping.

Celtic responded with Griffiths sending a looping header onto the roof of the net before 'keeper Ripley blocked efforts from Stefan Johansen and Patrick Roberts.

Nir Bitton was the next Celtic player to be thwarted by Ripley as he parried his long-range strike before stopping another powerful effort from Griffiths.

Celtic's pressure finally paid off when they were awarded a 26th-minute penalty. A clumsy challenge by Morgaro Gomis brought down Roberts just inside the box but Griffiths, who was without a goal in four games, drilled the resultant spot-kick low and wide.

The 'keeper was called into action moments later when he first punched away a stinging strike from Kieran Tierney before getting back to his feet to block a fierce follow-up from Roberts.

However, Ripley was finally beaten as Griffiths made amends for his penalty miss. Patient build-up play around the box eventually ended with Tierney pulling the ball back for Griffiths to apply a simple one-touch finish.

The home side made a positive start to the second half and thought they had grabbed a 55th-minute equaliser after McDonald fired home Louis Moult's cross but the Australian striker was adjudged to have strayed offside and his effort was immediately chopped off.

However, the former Hoops striker wasn't to be denied on the hour mark as he fired Motherwell level.

Cadden forced his way past Tierney down the right and cut the ball back for McDonald, whose first-time strike took a slight deflection off Dedryck Boyata as it flew past Craig Gordon.

Ripley had been keeping his side in the match, making a number of good saves from Roberts before his gaffe helped restore Celtic's advantage.

The on-loan Middlesbrough shot-stopper allowed a low strike from Griffiths to slip through his fingers and under his legs after the Hoops striker connected with a cut-back from Tierney.