Bezzecchi, who was narrowly denied victory in Saturday's Sprint race at Round 2 of the series by Red Bull KTM's Brad Binder, now leads the championship standings by nine points from official factory Ducati rider Francesco Bagnaia, who crashed out of second place on Lap 18.
“I'm really, really happy and I have no words because today, honestly I woke up with a strange sensation like I knew I could go fast,” Bezzecchi said.
“But honestly, I didn't expect to go so fast and I was really scared from the wet, because normally I'm not very good with the MotoGP in the wet.
“But today was fantastic. I had an incredible feeling from the first minute of the Warm Up and I just enjoy a lot with my bike.
“I was speaking to the bike just to stay concentrated and it was really, really tough, but it is an incredible feeling,” he added.
“I want to thank all the VR46 Riders Academy, Ducati, all my team, my family, my friends – everyone that supports me every day.”
Bezzecchi had also demonstrated excellent pace in the dry at Rio Hondo in practice, and when Sunday turned out wet, he said he felt ‘desperate'.
“I felt this morning that I was really good, but when I saw the rain I was desperate honestly, because yesterday I felt really good on the bike and felt that if I didn't make any mistakes, I can really try to win [on Sunday],” he said.
“This was the first time that I thought this in my career, but when I saw the rain it was a disaster for my emotions.
“Then in the Warm Up, I jumped on the bike and the feeling was incredible in the wet, so I said, ‘Okay, I can do this', and the race was incredible.”