The Avintia Ducati rider has stepped up to MotoGP in 2021 having finished runner-up in the Moto2 standings last year, and races on the same grid as brother Rossi for the first time.
Struggling with the change of grip in the race compared to the practice sessions, Marini ended up third out of the four rookies in 16th in last Sunday’s race.
“Sincerely, it’s bad, I’m not happy about my race, but not about the position – the pace in particular, because I expected to be much faster,” he said.
“But I struggled a lot, especially I feel the grip was a little bit different compared to all the other practices and was not easy for me to stop the bike in the last phase of entry, and also in the middle of the corner I was not able to do corner speed.
“So, I was slow in all the corners in the circuit, it was not one place in particular.”
Asked what it was like to share the grid with Rossi for the first time, Marini added: “Sincerely, when I was on the grid I didn’t think about this, just I was focused on my race.
“I nearly forgot that he was also on the same grid at the same moment, and I didn’t think about this.
“But it was a very big emotion to stay there for the first time to see the MotoGP class, it’s fantastic.”
Photo by: SKY Racing Team VR46
Marini’s Avintia team-mate Enea Bastianini led the rookie crop, recovering from a “disaster” opening three laps to finish 10th – though his progress late on was stifled by arm pump.
“I learned a lot because my start was so slow, and the first three laps were a disaster for me with the new tyre,” Bastianini said.
“It was difficult, but after these three laps I did some good lap times and step by step I arrive in 10th position.
“After that, I tried to push more but the last six laps my arms were so tired and it was impossible to arrive in the seventh position.”
Bastianini’s wasn’t the only impressive rookie display, after Pramac’s Jorge Martin rocketed from 14th to fourth at the start and briefly held third on the opening lap.
Admitting running that high “took its toll on me”, Martin plummeted to 15th when his tyres faded away.
“I knew I was going to go well because I was doing very good starts in practice compared to the other Ducati riders,” Martin explained.
“I knew I could pass three or four, but not 12.
“At the beginning I was comfortable, but it’s not my position and it took its toll on me, I think in the end finishing 15th and scoring a point is not a bad result.
“But I think the real position today is 12th and I’m happy with my work and the way I rode.”