M-Sport World Rally Championhship team boss Malcolm Wilson admitted he was "really disappointed" with lead driver Mikko Hirvonen after Rally Finland.
Hirvonen, who won his home WRC round in 2009 and finished on the podium four years in succession, was a distant fifth and almost three minutes behind the winner last week.
"I have to go on record and say I am really disappointed with Mikko," said Wilson.
"I thought this event was a great opportunity for him - especially after we had been so strong last year, with both Thierry [Neuville] and Mads [Ostberg] leading the event in our car.
"It was always going to be a massive challenge to beat Jari-Matti [Latvala] and Seb [Ogier], the two fastest drivers in the world, but I certainly thought we could be on for a strong podium. Sadly, we haven't been."
Wilson thinks the key is for Hirvonen to start enjoying rallying again.
"I don't think he's enjoying his driving any more," said Wilson.
"If you're not enjoying your driving then it's never going work.
"You listen to WRC Live and you hear the other guys, like Kris [Meeke] and Paul [Nagle], laughing about what they've just done - that is part of it.
"You have to enjoy it. It's the same when you go to work, if you don't go to work, you're not going to do a good job."
Hirvonen believes things went awry in Finland because he was over-thinking his driving and set-ups.
"On Friday I was really happy with my driving and I got everything I could from the car and the car was perfect," he said.
"But then when you start to think about things - 'it's a bit more slippery here, maybe I should be softer on the damper...' - the commitment goes a little bit and you begin to lose out and the others begin to pull away.
"For sure it would be fantastic to be on the podium in front of everybody, but it's not the end of the world."