Following a violent crash during warm-up for the Indonesian GP, Marquez suffered a new episode of the diplopia – or double vision – which previously sidelined him for three months late last year.
Missing the Argentina GP while he recovered, the Honda rider was given the all-clear to continue racing this weekend at his beloved Circuit of the Americas.
And it only took Marquez five laps to get back up to speed, the seven-time COTA winner going top of the pile with a 2m04.469s just 15 minutes into FP1.
He would stay at the top of the timesheets with that lap until just under 12 minutes to go, when Maverick Vinales on the Aprilia went 0.096s clear with a 2m04.373s.
Having made a breakthrough with set-up on the Aprilia in Indonesia and carrying that through to a strong Argentina weekend, Vinales came into COTA confident he could be strong.
Rins had his session interrupted at around mid-distance, with his GSX-RR slowing on the exit of Turn 11 onto the back straight.
But the 2019 COTA race winner managed to get back out on track on his second Suzuki and lit the timing screens up in the dying stages with a run of three-successive sessions-topping times. This run culminated in a 2m04.007s, which put him top of the pile at the checkered flag by just 0.008s.
A late charge from Vinales threatened Rins’ lap, but the Aprilia rider had to settle for second ahead of factory Ducati rider Jack Miller.
Reigning world champion Fabio Quartararo led the session in the early stages and was fourth at the checkered flag, 0.0443s off the pace, while Marquez completed 17 laps in fifth.
He headed Honda teammate Pol Espargaro, who stopped on track at Turn 10 after the checkered flag.
First while championship leader Enea Bastianini guided his Gresini Ducati to seventh ahead of current points leader Aleix Espargaro on the second of the Aprilias. Trailing the Argentina winner was LCR Honda’s Takaaki Nakagami, while Johann Zarco (Pramac Ducati) rounded out the top 10 ahead of 2020 world champion Joan Mir on the sister Suzuki.
The KTM contingent was led by Brad Binder down in 12th with a 2m04.983s, with Francesco Bagnaia on the factory team Ducati and Pramac’s Jorge Martin behind him.
COTA has been partially resurfaced from Turns 2 to 10 and Turns 12-16 since last October’s race after bumps led to safety concerns and an ultimatum from the riders.
However, several corners – including the fast, plunging turn 10 left-hander – still appear to have some aggressive bumps.
FP2 for the 2022 MotoGP Americas GP gets underway at 2:10pm local time.