The Frenchman struggled in the first three races of the year with unspecified car problems, but a switch of chassis for the last race at Sakhir helped him and his team overcome the issues.
Having been under the spotlight because of a troubled end to 2012 - which included a race ban for causing a pile-up at the Belgian Grand Prix - Grosjean was coming under pressure to deliver.
But team principal Eric Boullier says that with the car issue now sorted, Grosjean is perfectly placed to build on what he did in Bahrain and deliver more success over the remainder of the campaign.
"If you look at the season so far, except for the car issue, he didn't have troubles," said Boullier.
"He was having good starts, good first laps and good overtaking manoeuvres. So I think he is okay now.
"But Bahrain was a big relief. He put a lot of effort in to rebuild himself after 2012, and it is now paying off.
"He had a frustrating first three races, but he can now build on this and keep the momentum."
Boullier insists that the key to Grosjean's turnaround in Bahrain was not just the new chassis that the team brought for him.
"It was not only the chassis, there were a lot of details to understand why it didn't work," he said. "But the team did a good job and we found a couple of things that made Romain happy with his car.
"So when he started to enjoy driving, it was a different world. I know he is starting his season now."
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