Pastor Maldonado accuses Williams of favouring Valtteri Bottas
Maldonado qualified only 18th for the US Grand Prix while Finnish rookie team-mate Bottas put his car in ninth place on the grid.
Williams rejected any suggestion of favouritism or dirty tricks after their departing Venezuelan driver Pastor Maldonado made thinly-veiled accusations against the Formula One team on Saturday.
Maldonado, who is leaving after next week's finale in Brazil, qualified only 18th for the US Grand Prix while Finnish rookie team-mate Valtteri Bottas put his car in ninth place on the grid.
"I think in my car somebody is playing with the pressure and the temperatures. But one more race to go, so great," Maldonado said.
"You need to ask the team, to the guys that are working on the car, it is quite clear," he added when asked to explain the difference between him and his team mate. "It is a question for them."
Maldonado has scored the former champions sole point of the season so far and has become increasingly frustrated by their performance.
The divorce between last year's Spanish Grand Prix winner and the team was sealed earlier in the week when Williams announced Maldonado would be leaving and Ferrari's Brazilian Felipe Massa taking his place.
Maldonado, who has considerable financial backing from state oil company PDVSA, further stirred up controversy by telling reporters in Austin that he had "delivered more to the team than they did for me."
He has also made clear he is happy to be leaving and had sought the move.
Williams deputy team principal Claire Williams dismissed his accusatory words as merely those of a frustrated driver speaking in the heat of the moment.
"It's a big adrenaline rush for drivers, isn't it?," she said. "People say things after these kind of situations and we'll go back and talk to the engineers and see what happened. But never in Williams, in our experience and our history, would we ever do anything like that."
Williams denied there was a bad atmosphere within the team, winners of nine constructors' titles in their heyday between 1980 and 1997.
"When we are behind closed doors, it's not acrimonious," she said. "There's not that kind of atmosphere within the team. Pastor has said he wants to go to another team and that's completely fine. Drivers do that. This is Formula One, it's the nature of our business."
Maldonado has been linked to Lotus, who need a replacement for Kimi Raikkonen and are also in need of funds, and cash-strapped Sauber for 2014. Bottas, whose place at Williams in 2014 has been confirmed, was fastest in the first phase of qualifying and hoped he could finally score some points on Sunday. The Finn also dismissed talk of any favouritism or anything shifting in his favour.
"I haven't noticed anything," he said. "Everything is still the same, the cars are the same and I'm just doing my best here."
Williams said the Finn's performance had been a big morale boost.
"It just shows that Williams is competing again and it just feels so great," she said. "He did a great job the whole way through qualifying today."