In his first proper measurement against the rest of the field since rejoining Yamaha from Ducati, Rossi finished the final day in third position behind last year's title rivals Dani Pedrosa and Jorge Lorenzo.
The Italian had been fourth quickest on the first two days.
Team director Massimo Meregalli said Rossi had clearly been buoyed by his performance.
"He removed a lot of weight from his shoulders," Meregalli said.
"I see him very happy because he is finally back riding a bike that he enjoys, which is what he was looking for. I can't say more than that.
"The team has performed extremely well and both riders have worked very hard, it's been a successful start to the year."
Rossi agreed that the first test had delivered everything he could have hoped for.
"I'm very happy, all three days were very good," he said.
"We worked hard on the bike and improved day by day.
"The third day was the best, we were able to stay less than half a second from pole position and the lap time is better, which is interesting.
"Today we finished third in the standings, which is theoretically the front row, so I'm very happy with this first test."