Hearts boss Derek McInnes was left furious after Celtic were awarded a controversial late penalty in their 3-2 victory over Motherwell.Huge late drama unfolded in the Scottish Premiership title race, as Kelechi Iheanacho’s penalty in the ninth minute of stoppage-time secured the Hoops three points to set up a mouth-watering final day title showdown with Hearts.GettyIheanacho clinched victory for Celtic with virtually the last kick of the game[/caption]McInnes’ side could have clinched the trophy with a win if their nearest challengers lost to Motherwell.The Jam Tarts kept their side of the bargain with a 3-0 victory over Falkirk, and looked on the cusp of glory as Celtic and Motherwell remained at 2-2 when the full-time whistle blew at Tynecastle.A draw for Celtic at Motherwell would have left Hearts three points clear of the reigning champions with a six-goal superior goal difference, and just one game remaining.However, late drama unfolded at Fir Park, as Celtic were then awarded a penalty with virtually the last kick of the game.View Tweet: https://t.co/kwFO6mOH7tFormer Hearts midfielder Sam Nicholson was penalised for handball after jumping to head the ball away against Celtic’s Auston Trusty, with a VAR review called.The ball appeared to hit Nicholson’s raised hand right in front of his head, however replays appeared inconclusive.But the decision stood, with Iheanacho coolly slotting away the spot-kick to snatch victory for Celtic, sparking wild scenes in the away end as Hoops fans poured onto the pitch to celebrate.‘We’re up against everybody’Celtic’s last-gasp victory set up an enthralling final day showdown for the league title at Celtic Park on Saturday between themselves and Hearts with the Jam Tarts taking a one-point lead to Glasgow.But the decision which created the winner-takes-all clash left Hearts boss McInnes furious, who slammed the penalty call at Motherwell.He told Sky Sports: “When they were checking a 96th minute penalty, you assume they [Celtic] are getting it.GettyCeltic’s fans spilled onto the pitch as they forced a thrilling final-day decider[/caption]Replays of the Hoops’ controversial penalty decision were unclear at best“It’s disgusting. We’re up against everybody. I don’t think it’s a penalty.“If I’m Motherwell, I’m really disappointed. It’s so poor and it looks as though [Celtic] have been given it. They are very fortunate.“It’s going to the last game. We’re delighted to be part of it.“To do it, we’re going to have to go and get a positive result. What a game it’s going to be.”McInnes’ frustrations were compounded by the fact that he felt Hearts were denied a penalty in their last match against Motherwell.His side were held to a 1-1 draw at The Well on Monday, and saw a penalty appeal waived when Alexandros Kyziridis appeared to be tripped by Motherwell‘s Tawanda Maswanhise.McInnes suggested the league is against Hearts as he blasted Celtic’s penalty decisionMcInnes said on Monday that he’d discussed that incident with head of referee operations at the Scottish FA Willie Collum, and that the ex-referee had agreed that his side were hard done by.Scottish Premiership title picturePrior to their winner, Celtic would have needed to win by three or more goals on Saturday to leapfrog Hearts at the top of the table.However, a win by any margin would now be enough to win a record 56th title, and a fifth league title in a row.As for Hearts, they will become the first side from outside the Old Firm teams to be crowned champions for 41 years with a draw or better.The visitors won their previous meeting at Celtic Park this season, securing a 2-1 victory back in December.Either Celtic or Rangers have won the league title in Scotland every season since Aberdeen’s last victory in 1985 under Sir Alex Ferguson.