Marquez's last to 6th charge: 'I saw an alarm, the bike was crazy!'
But an incredible comeback, on his racing return from diplopia, signalled the Spanish star should have been fighting for an eighth COTA victory.
Marquez lost 4.021s to eventual winner Enea Bastianini on the opening lap and eventually took the chequered flag 6.617s from the Gresini Ducati rider, in sixth.
Subtracting the time lost on lap 1 alone would put Marquez 2.596s from Bastianini and in the wheeltracks of third place Jack Miller. But that doesn't take into account time Marquez also lost behind slower riders and while performing 20 plus overtakes (some riders more than once).
"On one hand I am disappointed because it is clear we had the speed. I was able to enjoy the race a lot, coming through from the back, but 25 points were possible today," Marquez confirmed.
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What happened to Marc Marquez at the start?
When the red lights went out, Marquez RCV limped away from his ninth-place grid slot as if the pit lane speed limiter was still engaged.
"We had a technical problem," Marquez said. "Honda is investigating, but they know more-or-less already [what it is].
"Since I arrived on the start I saw some alarm [warning light on the dash]. I tried to start, but the bike was crazy and I thought it was something big because until the first corner there was no [power] from the bike.
"I even checked, 'did I put the pit limiter?' but no. The alarm stayed [on] for all the race but luckily after the first corner, when the holeshot devices disengaged and everything, the bike worked more-or-less in a good way.
"It was not perfect, because there was something still wrong, but it worked in a good way.
"And from that point, we started another race."
Having limited his fast laps throughout the weekend due to a lack of general fitness from resting the Mandalika eye injury, Marquez now faced the worst-case scenario from a physical viewpoint; fighting through the field at one of the most exhausting tracks on the calendar.
"I knew that riding at 100% for all the laps would be impossible, but I gave everything and then when 5-6 laps remained my body said 'okay, that's it' and I just tried to finish the race," said Marquez, who set the second fastest lap, 0.032s behind Bastianini's new record, on lap 13 of 20.
"Even like this I was able to ride in a good pace. Okay, the result is not the one that we expected, but if we check how we started and where we were at the first corner, with how we finished, we can say that we built a lot of confidence.
"My target was to build confidence and try to not have any crashes all weekend - because the doctor said to me that everything was fixed [in my eye], but I'm scared about my health and it was a recent impact, just three weeks ago.
"So I just tried to ride in a good way and this was most important."
Given that the huge Mandalika accident was still fresh in his mind, the warning light on his dash must have added further mental tension during the race.
"It was not easy after that start to the race to get the confidence and push," Marquez admitted.
"But I came here to compete. Of course I tried to control myself to not push a lot and in the race I said 'okay, I'm last but I don’t fix any target. I will do step by step'.
"I passed the riders one by one, even if I did a big mistake into turn one, but this was a consequence of Vinales' move on the brake point and then I also needed to release the brakes.
"But I was very calm, just trying to control myself and when in the last laps I felt like I was tired, I didn’t push. Pecco was there but I said 'sixth is enough'.
"The most important was to finish the race, but we took a risk and I pushed."
Fabio Quartararo: 'Marc will be a title contender this year'
Marquez finished the race in a battle with reigning world champion Fabio Quartararo, beating the Yamaha rider by 0.143s.
"At the end we had a really nice battle with Fabio, but when the race finished, I was destroyed."
"I think that Marc will be a title contender this year, I will give my best to be a title contender, and so I think we will have more [battles] like that, for better positions," Quartararo smiled. "And riding behind an eight-time world champion, you always learn something."
Francesco Bagnaia said: "If Marc didn't miss the start for sure he would have been at the front too. I think Enea was the only one today that would have been able to fight with Marc."
Marc Marquez: Sixth a satisfaction
Despite the potential race-winning speed he had shown in the race, Marquez insisted he didn't feel frustrated at the outcome.
"To be here this weekend was a satisfaction and to finish the race in sixth position also is satisfaction, if we check how we start the race," he said.
"It's true that it looks like when you are in your worst moment, everything [happens]! We almost never had a technical problem during all the years and today, when I need more the help [on my comeback], we had a technical problem.
"But this is something that happens. I'll kept going, kept pushing and I want to say thanks to the team – even though we had a technical problem – because they helped me a lot. They gave me the confidence I need and this is important."
Pol Espargaro: Maybe the hardest MotoGP race of my life
Team-mate Pol Espargaro, struggling badly with a stomach illness all weekend, was one of the many riders passed by Marquez, for tenth place, on lap 7.
Espargaro gritted his teeth and eventually finished in 13th.
"Physically, this was maybe the hardest MotoGP race of my life," he said. "With about ten laps remaining I was honestly thinking about retiring from the race because I was feeling so weak.
"But I saw that we were in the points and I wanted to do it for the team. I was slow and the fast changes of direction were almost impossible. I am finished, I am exhausted.
"Now we can go home and recover and prepare for the races in Europe. The bike’s potential is much higher than what we have shown and where we are in the standings.”
Espargaro remains the top Honda rider in the world championship standings, in eleventh place and now 38 points from Bastianini. Marquez is 13th and 40 points from the top, having missed two of the four races this season.