Loris Capirossi says the lack of practice time at Motegi ruined Suzuki's chances of carrying its testing form into the race.
Although Suzuki was very quick over the winter, it has yet to turn that speed into race results. Chris Vermeulen and Capirossi qualified fourth and sixth for the Japanese Grand Prix, but could only finish 10th and seventh respectively.
Capirossi said the extra track time available in testing had been key to getting the Suzuki on the pace, and that the team was struggling without it.
"I am disappointed with seventh, because this is not our proper position as we have better potential than that," he said.
"This winter we went very well because we had enough time at tests to work on the bike, but here this weekend we did one dry practice and everything else in the wet.
"We never found the best setting and we started the race with one we hadn't tried here. The bike was not too bad, but I never really found a good rhythm and feel from the tyres. I want to say that I am really sorry to all my team and everybody that has been working so hard this weekend. We need to go better than that and this weekend we just didn't perform well enough."
Vermeulen was also hampered by a gearshift problem, which saw him tumble down the field after briefly holding second at the start.
"I'm really disappointed today, because I got a good start, the bike felt good and I thought a decent result would be possible," he said. "I pushed as hard as I could and tried to hang on to the back of Valentino (Rossi).
"From about the second or third lap I started to have a problem shifting gear heading into the turns and it made it difficult to stay consistent. I felt like I'd got it under control, but then the problem got worse from about lap six as I lost all shifting up and down without having to shut the throttle or use the clutch - so it was quite difficult.
"Other than that the bike worked really well and I felt like I could have challenged somewhere close to the front, but that's all ifs, buts and maybes and we now have to make sure what caused the problem today never happens again."
The Australian remains optimistic that Suzuki can recapture the form that saw it challenging Ducati and Yamaha in testing.
"If we can keep the speed we've had recently we will go to Jerez in a positive frame of mind and if we can iron-out all the little things, then I am sure we can start to challenge for podiums," said Vermeulen.