Bitter rival Formula One bosses Christian Horner and Toto Wolff do finally agree on one thing – they want Sunday’s epic title decider at the Etihad Airways Abu Dhabi Grand Prix to be a clean race. Off the circuit, the duo have been scrapping almost as hard as their drivers Max Verstappen and Lewis Hamilton, and the rivalry has become so ill-tempered, furious Wolff hurled his headset to the floor in Jeddah while angry Horner was punished for his Qatar outburst. Despite the bad blood, the Red Bull boss and his Mercedes counterpart want the final race of the year decided on the Yas Marina Circuit track and not in front of the stewards or by a crash. After 21 races on four continents, Verstappen and Hamilton go into last race dead level on points, which has not happened in F1 since 1974. If Hamilton wins he will make history as the first driver to win eight championships, but a victory for Verstappen would not only be his first title but herald the first non-Mercedes champion of the hybrid era. “We go to Abu Dhabi tied in the world championship and leading by virtue of race wins, it’s whoever finishes ahead,” Horner said. “It’s just a straight fight as it has been all year. Now Mercedes have won three in a row, Max won two before that. Who’s going to come out on top? I have no idea. “Obviously we’ve seen their [superior] performance in recent races. The form is with Mercedes but Max has fought like a lion and given it everything.“ Red Bull are also eager to discover the effect of the dramatic changes to the Yas Island track, which throws in another curveball after teams had wrestled with the demands of brand new events in Qatar and Jeddah. “They’ve changed it again so there’s another variation in the championship,” added Horner. Reflecting on Verstappen’s tactics in Saudi Arabia - where Hamilton accused the Dutch driver of brake-testing after colliding into the back of his car - Wolff said: “It was hard, very hard, maybe over the line hard. We just want to have a clean championship and someone win. If it’s Max in the end then I have peace with that but it needs to be a fair race.” Verstappen would become champion if they crash out together in Abu Dhabi. Although the duo are tied on points it would go to a countback and Verstappen has one more win than Hamilton. “Max he has more wins, that’s still an advantage,” added Wolff. “It’s just important to have a great, great end of the season, two fantastic drivers racing each other. “Everybody has had their fair share of bad luck. Max lost a lot of points at Silverstone, wasn’t at all to blame in Hungary but then maybe gained a little bit back in Spa and we had our engine penalties. “In the end it’s going down to the wire. That’s how the sport should be. It’s good.” But the championship has been one of the most ill-tempered in recent memory with other team bosses suggesting the behaviour of the duo was becoming unacceptable. Wolff slated his rival for chasing publicity and creating a pantomime, so Horner hit back joking his 6ft 4in opposite number would make the perfect pantomime dame. There has also been rolling accusations on both sides and a strong undercurrent of suspicion. In Brazil, Red Bull claimed the remarkable turn of speed that allowed Hamilton to win from the back row of the grid was down to rear wing movement that was illegal in the spirit of the rules if not the actual wording. Prompted by Red Bull, FIA stewards examined Mercedes’ rear wing and it failed by just millimetres, so Hamilton was hurled to the back of the grid. Mercedes hit back saying their rival was seeing “ghosts” as their wing passed a barrage of extra tests. Even former F1 boss Bernie Ecclestone piled in on Wednesday, accusing Wolff of “bullying” tactics to increase the pressure on 24-year-old Verstappen. Earlier in the year there had been a ‘limbo’ rear wings row. The sport’s beleaguered officials even introduced a string of beefed up tests in an effort to keep up. The pressure cooker finally exploded when Horner was called before the stewards in Qatar and punished for accusing a track marshal of “going rogue” and stewards of losing control of their staff. In Saudi, it was Wolff’s turn as he hurled his radio headset at the floor in fury.