At the start, with all cars starting on wet tires, Newgarden made a brave three-wide down-the-inside pass on the front-row starters, but ran out of track on exit and was passed by Andretti Autosport-Honda’s Rossi, Chip Ganassi Racing-Honda’s Dixon and the second Andretti car of Takuma Sato.

With the track now mainly dry, almost everyone pitted for slicks at the end of the lap. Will Power got massively shuffled back from his eighth starting spot and was thrashing around in 15th.

Out of the pits, Rossi was in front, but after an excellent pitstop, Team Penske-Chevrolet’s Helio Castroneves dived inside the #98 car at Turn 10 to take the lead, with Newgarden third and Ryan Hunter-Reay fourth, ahead of Dixon after his relatively poor stop.

These five were followed by Simon Pagenaud (Penske), Charlie Kimball (Ganassi), Carlos Munoz (AJ Foyt Racing-Chevrolet), Graham Rahal (Rahal Letterman Lanigan Racing-Honda), Conor Daly (Foyt).  

Outside the top 10 were Sebastien Bourdais (Dale Coyne Racing-Honda), Kanaan (Ganassi) and Will Power (Penske). Soon struggling were Sato with a power (turbo wastegate) issue, and Ed Carpenter Racing’s Spencer Pigot who spun on a damp patch on slicks.

On Lap 6, the full-course yellow emerged for James Hinchcliffe’s stranded Schmidt Peterson Motorsports-Honda, which had suffered a gearbox problem. By this time, Dixon had grabbed fourth from Hunter-Reay who like Rossi was running on blacks, which had been struggling to get up to temperature throughout this cold weekend.

At the restart, Newgarden tried to pass Rossi, but instead found himself demoted to fourth as Dixon went around the outside of him even before the Bus Stop chicane. Lap 9 was a poor one for two of the other Penske drivers, too, as Pagenaud drifted back to ninth behind Munoz and Rahal, and Power was passed by Dale Coyne Racing’s Ed Jones.

Kimball got around Hunter-Reay for fifth on Lap 10, back to where he started, and soon Munoz was up on Hunter-Reay’s rear wing, looking to pass.

The second Schmidt Peterson car of Jack Harvey, making his IndyCar roadcourse debut, pitted from 16th on Lap 12. Marco Andretti would follow suit on the next lap. Up at the front, meanwhile, Rossi was 1.3sec behind, but more concerned about Dixon who ran one second behind him.

Sato, after his engine issue, had rejoined one lap down, but he couldn’t get up to speed and coasted to a halt in Turn 6, bringing out the second caution, and almost everyone pitted. The exceptions were Pigot, Chilton, Hildebrand, Andretti and Harvey who thus filtered to the front.

Behind, Castroneves came out just ahead of Rossi, with Hunter-Reay and Newgarden jumping Dixon again. Kimball came next, ahead of Rahal, Pagenaud, (the big winner) Power and Bourdais.

The restart on Lap 17, saw the red-shod Andretti cars of Rossi and Hunter-Reay take Castroneves up the hill and into the Bus Stop, as up ahead Andretti (reds) passed Hildebrand (blacks) and the pair of them zapped Harvey into Turn 1 the next time by.

Into Turn 1 on Lap 20, Andretti let Rossi through into third. Further back, Dixon passed title rival Newgarden for ninth, and teammate Tony Kanaan had passed Power and Pagenaud for 14th. It looked like the Penskes had too little straightline speed, with too much downforce.

Hunter-Reay passed teammate Andretti into the Bus Stop on Lap 20 to take fourth, as Rossi passed Chilton for second. The 2016 Indy 500 champion was only one second behind leader Pigot. However, Hildebrand and then Pigot stopped their ECR cars on Laps 22 and 23 respectively.

Rossi now led Hunter-Reay by 3.6sec, with Chilton two seconds further back, chased by Castroneves. Yet Rossi – who’d suffered a fuel hose and probe issue at the previous stop – had to pull in for a stop on Lap 24, the team having discovered they hadn’t delivered all the necessary fuel.

Hunter-Reay’s lead was 4.7 over Dixon, Andretti, Newgarden, Rahal, Kimball, Bourdais, Kanaan, Pagenaud, Power and Munoz as the top dozen.

On Lap 27, out came the yellows once more, as Sato created a pall of smoke, and that allowed Rossi, Pigot, Chilton and Hildebrand to cycle to the front once more, chased by Hunter-Reay, Castroneves, Dixon, Newgarden, Rahal, Power (another great stop from the #12 crew) and Kimball. Most were on blacks; the exceptions were Chilton, Hildebrand and Andretti.

Up to Turn 4, the Bus Stop, Dixon passed Andretti for seventh, and Rahal demoted Newgarden. Further around the lap, Kimball slapped a barrier following contact with Daly and fell backward.

Rossi was taking full advantage of a clear track ahead, and by half distance, Lap 30, had well over 3sec in hand over Pigot, and seven over Chilton and Hildebrand. Behind this quartet, the battle for fifth was hugely entertaining, Hunter-Reay appearing to hold up Castroneves and Dixon. The Kiwi passed the Brazilian around the outside into the Bus Stop to grab sixth. The following lap, RHR demoted JRH to snatch fourth, and Rahal passed Andretti.

Hildebrand stopped on Lap 37 and Pigot on 38, leaving Chilton second but a full 12sec behind Rossi. Hunter-Reay had to hope so, because he was now struggling to line up a pass and hold off the looming Dixon behind. Hunter-Reay finally had to give way to the four-time champion on Lap 39, and the yellow Andretti car was soon under pressure from Castroneves and Rahal.

Rossi and Chilton stopped on Lap 42, handing Dixon the lead and a one-lap window to try and close that 12sec lead to Rossi who’d emerged in 11th but had to give way to the warm-tired Pagenaud. Dixon put his head down and charged, and then pitted, followed by Hunter-Reay, Rahal, Castroneves, Pagenaud and the two Foyt cars.

It was a long stop for Castroneves who then also violated the pit-out line, crossing fully onto the racing surface.

The following lap, Newgarden, Power, Bourdais, Kimball and Kanaan stopped, leaving the lead for Rossi, but there was high drama. Power beat Newgarden out, and then the championship leader slapped the safety barrier on pit exit, and got rammed by Bourdais doing the same thing. That pushed the #2 Penske and its debris out onto the racing line, and a closely-following Kanaan then also struck the barrier, causing a rear-left puncture.

Newgarden and Bourdais trailed back to the pits for repairs, as of course did Kanaan, while Pigot and Hildebrand took the opportunity for another fuel top-up from the ECR crew.

That left the order for the restart as Rossi, Dixon, Hunter-Reay, Castroneves, Rahal, Chilton, Power, Andretti, Kimball, Pagenaud, Munoz, Daly, Jones, Pigot, Bourdais as the Top 15.

All behaved themselves on the restart on Lap 49, and Rossi appeared to have the measure of Dixon, pulling a 1sec lead in three laps. Dixon appeared to be chasing hard, despite knowing his principal title rival was running 18th but he couldn’t quite match Rossi. On Lap 52, Kimball powered past Andretti into the Bus Stop chicane.

A little further back, Power and Kimball got around Chilton on Lap 54, but they were now six seconds behind Rahal who was running 1.5sec behind fourth-placed Castroneves with five laps to go.

Dixon kept the pressure on Rossi over the closing laps, the pair of them quite clearly a class above the rest, their best laps half a second clear of next fastest, Power.

The pair of them pulled six seconds clear of Hunter-Reay by the finish, but crucially Rossi kept Dixon at arm’s length and scored his second IndyCar victory, elevating himself to sixth in the points race.

Castroneves was followed home by Rahal, Power, Kimball, Chilton, Pagenaud and the Foyt cars, Munoz ahead. Harvey was 14th on his road course debut.

Newgarden’s trauma and Dixon’s runner-up finish means the Penske driver’s championship lead has been slashed to just three points heading to double-points finale at Sonoma in two weeks. 

Remaining mathematically in the championship are Newgarden on 560 points, Dixon pn 557, Castroneves on 538, Pagenaud on 526, Power on 492, Rossi on 476 and Rahal on 466.

Pos	#	Driver	Team	Gap
1	98	Alexander Rossi	Andretti Autosport	60 laps
2	9	Scott Dixon	Chip Ganassi Racing	0.9514
3	28	Ryan Hunter-Reay	Andretti Autosport	7.1592
4	3	Helio Castroneves	Team Penske	8.8938
5	15	Graham Rahal	Rahal Letterman Lanigan Racing	11.8863
6	12	Will Power	Team Penske	15.3787
7	83	Charlie Kimball	Chip Ganassi Racing	16.1639
8	8	Max Chilton	Chip Ganassi Racing	28.0410
9	1	Simon Pagenaud	Team Penske	28.2941
10	14	Carlos Munoz	A. J. Foyt Enterprises	29.4972
11	4	Conor Daly	A. J. Foyt Enterprises	30.2436
12	20	Spencer Pigot	Ed Carpenter Racing	32.3478
13	19	Ed Jones	Dale Coyne Racing	33.1533
14	7	Jack Harvey	Schmidt Peterson Motorsports	35.6826
15	21	J.R. Hildebrand	Ed Carpenter Racing	41.5905
16	27	Marco Andretti	Andretti Autosport	52.7948
17	18	Sébastien Bourdais	Dale Coyne Racing	54.0444
18	2	Josef Newgarden	Team Penske	2 laps
19	26	Takuma Sato	Andretti Autosport	4 laps
20	10	Tony Kanaan	Chip Ganassi Racing	14 laps
21	5	James Hinchcliffe	Schmidt Peterson Motorsports	55 laps