Max Verstappen dashed Ferrari's home hopes and won the Italian Grand Prix
Hamilton said he had not been feeling well on Thursday and Friday, when he was also up until midnight working with his engineers.
Ferrari's Charles Leclerc secured pole position for the Singapore Grand Prix on Saturday after a furious Max Verstappen was forced to abandon his fastest lap for fear of running out of fuel.
Leclerc had seized the lead at the start, and held it through an initial safety car period, before Verstappen made up for his poor getaway and passed the Monegasque -- whose tyres were fading fast -- with a late move around the outside.
IMAGES from the Belgian F1 Grand Prix
Sergio Perez won the Saudi Arabian Grand Prix from pole position in a Red Bull one-two on Sunday with Max Verstappen staying top of the championship after racing from 15th to second.
The Saudi Arabian Grand Prix is the penultimate race on this year's Formula One calendar
McLaren's Australian Daniel Ricciardo will join the Dutch 23-year-old on the front row for the first time since the pair were team mates at Red Bull in 2018.
Formula One championship leader Charles Leclerc took pole position for the inaugural Miami Grand Prix ahead of Ferrari team mate Carlos Sainz in a front row lockout in qualifying on Saturday.
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.
Charles Leclerc crashed at the end of qualifying for his home Monaco Grand Prix on Saturday
Images from the Tuscan F1 Grand Prix held at at Mugello, Scarperia e San Piero in Tuscany, Italy, on Sunday.
Charles Leclerc seized pole position for the Italian Formula One Grand Prix and sent Ferrari hopes soaring on Saturday while Mercedes' George Russell joined him on the front row once penalties were applied.
Norris said he had also been on pain-killers for a back problem and had not felt confident in the car, limiting his track time in the afternoon.
Formula One leader Max Verstappen handed his Red Bull team a home pole position for Saturday's sprint race at the Austrian Grand Prix after Mercedes rivals Lewis Hamilton and George Russell crashed in qualifying.
F1 is looking strongly to enter into the lucrative US market
Max Verstappen put Red Bull on pole position for Formula One's season-opening Bahrain Grand Prix on Saturday, with seven times world champion Lewis Hamilton alongside on the front row for Mercedes.
IMAGES from the Azerbaijan F1 Grand Prix held at Baku City Circuit on Sunday
Red Bull's Max Verstappen qualified third, after a power unit scare in the second phase sent mechanics scrambling to fix his car, with AlphaTauri's Pierre Gasly a stunning fourth on the grid.
Hamilton's 98th career victory, from his 100th pole position, was his third win in four races
Hamilton held on for fourth, but slipped from 18 to 32 points behind Verstappen in the championship standings.
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.
Ferrari's Formula One world championship leader Sebastian Vettel was handed a five-second penalty for colliding with the Mercedes of Valtteri Bottas on the opening lap of the French Grand Prix on Sunday.
Lewis Hamilton is now just three wins short of Ferrari great Michael Schumacher's all-time record 91.
Lewis Hamilton took his 98th career pole position in qualifying for the Bahrain Grand Prix on Saturday
Ferrari's Charles Leclerc held off Lewis Hamilton to win his first Formula One race on Sunday in the Belgian Formula One Grand Prix.
Verstappen leads seven times world champion Hamilton by six points with six races remaining and the pole at Austin's Circuit of the Americas was the ninth of the season for the Dutch 24-year-old -- and eighth in the last 11 races.
Verstappen took a grid penalty at the previous race in Russia and finished second after starting at the back of the field, his progress helped after late rain caused problems for others.
Alonso said he had huge respect for Hamilton and had no problems with him.
Formula One world champion Max Verstappen won the inaugural Miami Grand Prix for Red Bull on Sunday, slashing Ferrari rival Charles Leclerc's overall lead from 27 to 19 points after five races.
Red Bull's Max Verstappen won a chaotic and crash-halted Emilia Romagna Grand Prix at Imola on Sunday with Lewis Hamilton second for Mercedes and retaining the lead in the championship by a single point.
Lewis Hamilton, who started on pole position in Sochi hoping for a 91st Formula One victory to equal Ferrari great Michael Schumacher's all-time record, finished third behind Red Bull's Max Verstappen.
Red Bull closed the gap to champions Mercedes in the constructors' standings to one point.
The pole was the 95th of Hamilton's career and seventh in nine races this season, continuing Mercedes' 100% record in qualifying.
Lewis Hamilton won the Bahrain Formula One Grand Prix for Mercedes on Sunday after French driver Romain Grosjean had a miraculous escape from a fiery first-lap crash that ripped his car in two.
Formula One championship leader Max Verstappen lifted himself into a league of his own as he beat title rival Lewis Hamilton to pole position with a blinding lap in qualifying for the French Grand Prix at Circuit Paul Ricard.
Lewis Hamilton managed to make the most of the adverse conditions to take pole position for Sunday's race.
In a race of safety cars and surprises, Verstappen's former team mate Pierre Gasly made a first podium appearance in second place for Red Bull-owned Toro Rosso, a rare Honda-powered one-two.
Four days before the season-opening Australian Grand Prix, Horner said his team still had plenty of ground to make up, however.
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.