Although Franz Tost feels Jean-Eric Vergne has made a "lot of progress" this season, the team boss concedes he is in need of a big result.
Vergne has already spoken of the fact that he has suffered too many retirements this season, failing to reach the chequered flag in five out of 11 grands prix.
In those races he has finished, he has scored more often than not although his best results have been two P8s, Australia and Canada.
And although Tost says his driver has been doing a "good job" this season, he feels the Frenchman needs a big result to boost his confidence.
"He made a lot of progress during the winter months so he is much more [mentally] stable this year," Tost told Autosport. "He is doing a good job.
"Unfortunately he has had a lot of reliability issues with his car, but from the driving point of view he is fast, skilled, and I just hope he gets a really good result.
"Monaco [where Vergne ran as high as sixth before an unsafe release and ignition problems] would have been the kick to give him self-confidence to score a lot of points, and then everything becomes much easier.
"You need the results because this is the confirmation. Otherwise it's just talk, philosophy."