Esteban Gutierrez reckons his final lap in qualifying for the Japanese Grand Prix was compromised by a "really slow" Lewis Hamilton.
Both Haas drivers made it through to Q3 for the first time in the team's debut Formula One season, but while Romain Grosjean qualified eighth, Gutierrez could only post a time 1.9s off pole on his one and only lap in the final session, leaving him to settle with 10th on the grid.
The Mexican says he was caught out by a slow-moving Hamilton during his out-lap, which resulted in a sudden drop in tyre temperature.
"I was too cool on my tyres at the start of the lap because Lewis was really slow in the last part," Gutierrez explained. "He had no-one in front but he was really slow and I lost of temperature with my tyres and then starting the lap the tyres weren't there and I think I ran wide at Turn 7 and lost time.
"Let's not use it as an excuse. We have to get used to getting into Q3 and then we will know better how to manage Q3."
Gutierrez has come under fire on a number of occasions this season for being too slow to respond to blue flags. At the Hungarian Grand Prix Hamilton made a rude gesture towards Gutierrez after he appeared to ignore blue flags. At the following race in Germany Gutierrez again faced criticism, this time from Daniel Ricciardo, while Mercedes boss Toto Wolff accused the Mexican of "interfering" with Nico Rosberg's battle for the lead in Singapore.
Haas team principal Guenther Steiner, who has already come to Gutierrez's defence on several occasions this year, questioned Mercedes' "very odd" on-track behaviour at Suzuka.
"We have to ask Toto, because last time Nico was OK with it but Toto wasn't OK so we should maybe ask Toto what he thinks if he held Esteban up this time, because last time Nico didn't have a problem with Esteban but Toto did. So today Toto help Esteban up," Steiner joked.
"Joking besides they are doing very odd things Mercedes, they go very slow. They go fast first and then they slow down. I think they are very good at controlling some temperature before they get to the start/finish line, and it screws you up because some you have to go slower."
Steiner added: "I haven't studied what time they did because it's quite easy to find out with the GPS data how they slow down and all that stuff. It's always the same, if you are behind Mercedes you really don't know what they are going to do.
"How do you say in English if somebody is hanging around? Loitering, yeah loitering on the track."
It is not the first time Mercedes' qualifying tactics have been criticised by a Haas driver. At the Monaco Grand Prix, Grosjean stated the German team had ruined his chances of progressing to Q3 by driving slowly and causing "s---loads" of traffic during Q2.