Deadline-day signings Arne Engels and Luke McCowan grabbed their first goals for Celtic as the champions beat Hearts in a VAR-influenced William Hill Premiership encounter.Engels, Celtic's record signing, was handed his first start and netted from a 52nd-minute penalty.Referee Colin Steven gave the spot-kick for handball after being called to the monitor by video assistant Alan Muir after Nicolas Kuhn’s cross had struck James Penrice.Steven had also pointed to the spot in the first half when Lawrence Shankland’s header struck the arm of Liam Scales from close range, but he reversed his decision after studying footage.Hearts were well in the game until the 89th minute when McCowan collected James Forrest’s pass 20 yards out and curled a shot that Craig Gordon could only palm off a post and into the net.The Edinburgh side were on the end of a seventh consecutive defeat but they did not play like a side who are languishing in the lower reaches of the table.Engels was chosen ahead of Paulo Bernardo after making his debut off the bench against Rangers two days after joining from Augsburg for a reported £11m fee.The midfielder twice came close in the first half, arriving in the box at the right time to fire wide in the third minute and hitting the inside of a post after a good flick by Kuhn.Kyogo Furuhashi missed a great chance with Gordon rooted to the spot moments after being clattered by the Japanese striker.But Hearts came into the game and Shankland forced saves from Kasper Schmeichel from long range either side of the interval, after the visitors saw their penalty taken away.Steven Naismith’s side survived a double scare just before the break when Gordon denied Furuhashi and Penrice made an excellent sliding block to