Hamilton said he had not been feeling well on Thursday and Friday, when he was also up until midnight working with his engineers.
Max Verstappen fought back from a slow pitstop to win the US Grand Prix in Austin on Sunday as his Red Bull team clinched the Formula One constructors' title a day after the death of billionaire owner Dietrich Mateschitz.
Verstappen goes into the Formula One record books as the pole setter for the weekend, however, regardless of where he starts on Sunday.
Max Verstappen won the Spanish Grand Prix in a Red Bull one-two on Sunday
Hamilton, who had also topped Saturday morning's final practice session, never look like being challenged throughout the qualifying hour.
Australian Daniel Ricciardo won the Italian Grand Prix in a stunning McLaren one-two with Lando Norris at Monza on Sunday.
A teary George Russell celebrated the first Formula One Grand Prix victory of his career in Brazil on Sunday in a one-two finish with Mercedes team mate and seven-times world champion Lewis Hamilton.
It emerged then that former F1 racer Karun Chandhok's post-race video analysis for Sky Sports television formed part of what Ferrari had billed as "quite overwhelming" new and relevant evidence.
Lewis Hamilton did 94 laps of Barcelona's Circuit de Catalunya on the soft C2 compound in a sunny afternoon session
The Saudi Arabian Grand Prix is the penultimate race on this year's Formula One calendar
Reigning F1 champ warns Bottas about Hamilton rivalry
The sky's the limit for George Russell after the British youngster's stellar performance
Formula One world championship leader Sebastian Vettel won the Bahrain Grand Prix for Ferrari on Sunday in the German's 200th race start.
Lewis Hamilton won the Monaco Grand Prix for Mercedes on Sunday, nursing his car's worn tyres to the finish in a nail-biting victory worthy of the team's late great Niki Lauda.
In an afternoon of heroes, Sebastian Vettel played the Bond villain at Silverstone, notes Raja Sen, who returns to Rediff.com as F1 columnist!
Austin is a favourite track for the 34-year-old Mercedes driver and he will also be fancied to round up his Texan win tally to six on Sunday.
Hamilton has won the last three races, out of four so far in this COVID-19 affected season, and will start as favourite again.
The German, whose bid for a fifth crown petered out last year in mistakes and misfortune, had already been facing questions about whether he was making too many errors to win the championship.
Images from the Russian F1 Grand Prix in Sochi on Sunday
The German, taking his fourth win of the season, took the chequered flag 0.9 seconds ahead of Kimi Raikkonen with Hamilton finishing fourth after sportingly surrendering third place to team mate Valtteri Bottas on the last lap.
Formula One world champion Lewis Hamilton won the Hungarian Grand Prix from pole position for Mercedes on Sunday to go into the August break with a 24-point lead over Ferrari rival Sebastian Vettel.
Qualifying took place at a sunny Suzuka on Sunday morning after being postponed from its usual Saturday slot due to the approach of Typhoon Hagibis.
Max Verstappen won his home Dutch Grand Prix for Red Bull on Sunday and took the Formula One championship lead in front of a roaring, dancing army of fans hailing their hero with orange flags and flares.
The pole was a record-extending 88th of Hamilton's career and fifth of the season.
The pole, Vettel's 47th, ended a run of 18 in a row for world champions Mercedes who had Valtteri Bottas and Lewis Hamilton right behind the two red cars in third and fourth places.
Hamilton, eight points behind Vettel after 10 races, qualified 14th.
Formula One champion Lewis Hamilton won the Hungarian Grand Prix for a record seventh time on Sunday and extended his title lead to 62 points after relentlessly reeling in Red Bull's Max Verstappen.
An angry Leclerc dropped to fourth after Ferrari called him in again for slicks and then told him, too late, to stay out after Sainz also pitted and went directly from wets to the dry tyres.
Red Bull's Max Verstappen will be doing all he can to stop six-times world champion Lewis Hamilton completing a Mercedes hat-trick and matching another of Michael Schumacher's Formula One records in Hungary this weekend.
Lewis Hamilton won his home British Grand Prix for a record-extending eighth time on Sunday despite a 10-second penalty for a controversial first lap collision that sent Red Bull rival Max Verstappen crashing out of the race.
Charles Leclerc crashed at the end of qualifying for his home Monaco Grand Prix on Saturday
Lewis Hamilton was 'shocked' with the pace of Mercedes after notching a record-extending eighth pole position at the Australian Grand Prix ahead of team mate Valtteri Bottas as they thrashed their Formula One rivals in qualifying on Saturday.
The Briton's Finnish team mate Valtteri Bottas will line up alongside on the front row of the starting grid with Ferrari's Kimi Raikkonen and Sebastian Vettel behind them.
Ferrari's Charles Leclerc, starting on pole, finished second after defending hard against Verstappen with the two 21-year-olds banging wheels as the Dutchman forced his way past. Verstappen took the flag under investigation.
Team by team analysis of Sunday's Russian Grand Prix (listed in championship order):
Lewis Hamilton won a thrilling Italian Grand Prix for Mercedes on Sunday to stretch his championship lead to 30 points over Ferrari's Sebastian Vettel, who fought back to fourth after a first lap spin.
Lewis Hamilton tested positive for COVID-19 and was forced to miss last year's penultimate Sakhir Grand Prix in December.
Formula One's 'silly season' of rumour and speculation is heating up.
Lewis Hamilton lapped fastest overall for Mercedes in Hungarian Grand Prix practice
