Verstappen was ordered to hand back the lead, for going wide as Hamilton tried to pass on lap 37, but when he slowed Hamilton ran into the back of him.
Lewis Hamilton has won a twice-halted Saudi Arabian Grand Prix for Mercedes to go level on points with Red Bull rival Max Verstappen and set up a winner-takes-all title showdown.
On a chaotic night in Jeddah on Sunday, the first race in the Gulf kingdom took almost as many twists and turns as an already astonishing and enthralling rollercoaster season -- and also left a bitter aftertaste.
There were crashes and collisions, safety cars, red flags, and claims of dirty driving after seven-times world champion Hamilton hit the back of Verstappen's suddenly slowing car on the super-fast Corniche street circuit.
Extraordinary, at times angry, radio exchanges between the race director Michael Masi and the top two teams filled the airwaves.
With a bonus point for fastest lap, Hamilton moved alongside Verstappen at the top of the standings with 369.5 points after 21 races.
Verstappen, who finished second with Valtteri Bottas third for Mercedes, leads 9-8 on wins, however -- meaning that the Dutch 24-year-old will be champion if neither he nor Hamilton scores another point.
Mercedes extended their lead in the constructors' championship to 28 points and a record eighth successive title looking likely.
The final race is in Abu Dhabi next weekend.
Hamilton had started on pole but twice lost out to Verstappen, who began the day eight points ahead, at the standing re-starts.
The Dutch driver was ordered to hand back the lead, for going wide as Hamilton tried to pass on lap 37, but when he slowed Hamilton ran into the back of him.
"He just brake-tested me. I’ve just hit him, man, my wing’s broken," exclaimed the Briton. "That was dangerous driving dude."
Stewards summoned both drivers after the race and found Verstappen predominantly to blame, handing him a 10 second penalty that changed nothing.
The Dutchman did hand back the lead on lap 42 but took it back immediately.
Stewards then gave him a five-second time penalty for leaving the track and gaining a lasting advantage but Verstappen again let Hamilton through.
"We didn’t need to do that, Max," said his race engineer.
Mercedes told Masi they had not been given sufficient time to inform Hamilton that Verstappen would give back the place, and the Red Bull driver was also furious.
"What happened today is unbelievable and this sport is more about penalties than racing. For me, this is not Formula One," he fumed after being told he had been voted 'Driver of the Day'.