Former Celtic keeper Pat Bonner on Radio Scotland: "I didn't think that was a penalty at all. I thought Kieran Tierney pulled out of it just as Walker was going to strike it. I think the ref has made a mistake there."

It's getting pretty exciting at Tynecastle. Moussa Dembele goes through and forces a save from Hearts goalkeeper Jack Hamilton and Leigh Griffiths' improvised rebound effort is headed off the line by Alim Ozturk.

Celtic goalkeeper Craig Gordon was booked for dissent in the wake of the spot-kick award and then scorer Jamie Walker was also cautioned for his celebration.

Kieran Tierney is penalised for his challenge on Jamie Walker and Hearts have a spot-kick.

Image source, SNS

James Forrest runs at the Hearts defence again and the hosts have Jack Hamilton to thank for keeping the score at 0-1.

Tony Watt becomes the third Hearts player to be booked after some tussling with Scott Brown.

Bad miss from Leigh Griffiths for the champions. Last season's 40-goal man was allowed to gallop on to a long ball completely unattended, but put his left-footed lob into the side netting.  

Glaring miss from Tony Watt, playing against his former club, as he heads a cross from Hearts team-mate Callum Paterson wide from two yards out at the back post. 

BBC Scotland reporter Brian McLauchlin at Tynecastle: "When the shot came in from James Forrest, Stuart Armstrong was standing just a yard or so directly in front of Jack Hamilton. He was certainly in an offside position but the far-side assistant didn't put up his flag. When Hearts look at that again, they may feel that is a decision that went against them."

Hearts' Arnaud Djoum is cautioned for bundling over Celtic captain Scott Brown.

Replays of the goal show Celtic's Stuart Armstrong, who appeared to be offside, was right in front of the Hearts goalkeeper when James Forrest netted but was he sufficiently interfering with play?

Jamie Walker was set up for a shot as he cantered into the Celtic box but took too many touches and had to settle for a corner, which came to nothing.

Hearts had looked quite comfortable until that Celtic goal and now find themselves chasing the game slightly. They need to compose themselves and not get hurried so early in the match.

Hearts' forward Conor Sammon picks up the game's first booking for a sliding challenge on Kolo Toure.