Webber closed to within one second of Grosjean as the race approached halfway, but peeled into the pits for more new tyres before he had chance to attack. It was a comparatively early stop that put him onto a three-stop plan, but it soon became clear tha the Red Bull team had put its cars on split strategies; third-placed Vettel had conserved his second set of tyres well and was opting for just two stops. He remained out on track and began to take chunks out of the Frenchman's lead.
Grosjean made his second stop on lap 30, which promoted Vettel to the lead. Meanwhile, Webber had been setting quick lap times and leapfrogged Grosjean during the pit stops.
Vettel assumed the lead and remained out on track on his hard set of tyres for much longer than his rivals. His plan was to pull enough of a lead over Grosjean to enable him to make his second tyre stop and emerge still ahead of the Lotus racer. He needed more than 20 seconds to pull it off, but as Vettel stretched his worn tyres as far as he dared, it looked to have been a close-run thing.
Indeed, when Vettel finally changed his tyres at the end of lap 37, Grosjean moved back ahead. Vettel, armed with tyres that were eight laps fresher, was now the pursuer and went on the attack, slashing the two-second gap to his rival.
On lap 41 Vettel used the drag reduction system to storm past Grosjean on the start-finish straight and immediately pulled away.
Both men were still 15sec behind Webber, who was also setting some fast laps up at the head of the field. He peeled in at the end of lap 42 and put on a set of soft tyres, resuming in third place behind Vettel and Grosjean and immediately setting about chasing his rivals.
He reeled in Grosjean, and tried to slip past on the main straight on lap 47, but the Lotus racer defended stoutly. As they fought over the position, it gave Vettel the opportunity to eke out a few more seconds up at the front of the field. It was a crucial moment; if Webber had been able to quickly vault Grosjean, he might have been able to catch his team-mate and attack for the lead.
With three laps to go, Grosjean and Webber came up to lap a huge glut of back markers who were furiously fighting for position. Webber got a great run as they exited the chicane with two laps to go and squeezed between a defending Grosjean and the pit wall to seize the position. He sped clear, but any prospect of catching his team-mate had been extinguished.
Further back Felipe Massa raced strongly ahead of team-mate Fernando Alonso in the early stages, but a drive-through penalty for speeding in the pit lane during a tyre stop dropped him down the order. He eventually finished tenth, getting pipped by Jenson Button for ninth place at the last corner of the race.
Alonso had a quiet race by his standards, passing the impressive Nico Hülkenberg for fourth place in the closing laps of the race as the latter's Sauber encountered tyre wear problems. The Spaniard's points finish was sufficient to keep the world championship battle mathematically alive for another race.
Hülkenberg also fell into the clutches of Räikkönen in the last five laps, and the Finn pulled an audacious move around the outside of his rival into the chicane to take fifth place with two laps to run.
Nico Rosberg lost ground when he was penalised because his Mercedes team released him from his pit box into the path of McLaren's Sergio Perez during a pitstop. Ironically, Perez was later forced to make an emergency pit stop with a puncture when he clipped Rosberg's front wing with his left-rear tyre under braking for the chicane.
Rosberg attacked Gutierrez for seventh position in the closing laps, but had been advised by his Mercedes pit crew to keep an eye on his fuel levels. Mexican driver Gutierrez held his nerve to score his first points in Formula 1.
Daniel Ricciardo was in contention for a healthy slug of points in the early stages but was handed a penalty for gaining a position while going off the circuit and finished 13th.
Japanese Grand Prix, 13 October 2013
1 Sebastian Vettel (Red Bull)
2 Mark Webber (Red Bull)
3 Romain Grosjean (Lotus)
4 Fernando Alonso (Ferrari)
5 Kimi Räikkönen (Lotus)
6 Nico Hülkenberg (Sauber)
7 Esteban Gutierrez (Sauber)
8 Nico Rosberg (Mercedes)
9 Jenson Button (McLaren)
10 Felipe Massa (Ferrari)