The seven-time world champion returned to Formula One at the start of this season following three years in retirement but has failed to live up to expectations and has been regularly out-performed by Mercedes team-mate Nico Rosberg.
The German Bild newspaper reported this week that Schumacher had been warned by his team that he would not see out the next of his three-year contract unless he raised his game.
But that was today flatly rejected by Haug, who insisted the 41-year-old remained a key component of the team.
Asked to comment on reports of a Mercedes ultimatum, Haug said: “Well, this is an interpretation of what was said, but of course there was no ultimatum.
“We are currently a little bit handicapped with our car but I have no complaints and no regrets that we’re going to achieve our target. We need to work hard.
“We are sticking together and Michael is, for me, as good as he ever was and probably even better. He’s relaxed, concentrated. He doesn’t need anybody to defend him, certainly not me but we are very happy with the job he’s doing.
“If you take into consideration that he was not in Formula One for three years, we are heading in the right direction and there is certainly not an ultimatum.”
Schumacher certainly appeared to wring the maximum from his car today, finishing eighth in the opening two practice sessions for of Sunday’s Japanese Grand Prix at Suzuka.
More crucially, he was faster than team-mate Rosberg in both.
“I think Michael again showed today his class, his full commitment,” Haug continued.
“I’m happy and I think the Formula One community should be very happy to have Michael.”