Relive 1 NEWS NOW's live coverage of the 2018 IndyCar series finale, from Sonoma.
12:49pm: Lap 85 of 85 - SCOTT DIXON WINS FIFTH INDYCAR TITLE
Into the final lap! Hunter-Reay will take the win, but Dixon will come home in second to take the title. Rossi's early gaffe has cost him a title, as Dixon adds Championship number five to his collection.
Just five laps of the season to go! Dixon in pole position for the trophy, with Rossi slipping to sixth.
Less than 10 laps to go and it's all in Dixon's hands. He's pushed his lead out to 13 seconds over Rossi, and barring disaster, should be good to take the title.
Dixon under a bit of pressure from Power now! He's still got a hold of second, but the Aussie is hot on his heels. Rossi is in fifth, around nine seconds back.
That's it as far as pit stops are concerned for the rest of this race. Dixon sits four seconds behind Hunter-Reay, but eight seconds in front of Rossi. Race within a race now.
Dixon back up to second, but Rossi into fifth. If Dixon can keep this up though, the title is his.
Rossi and Dixon both pit for a tyre change coming to the close of the race. The Kiwi temporarily down to ninth as a result.
Rossi's on the charge! He's now into seventh, 12 seconds behind the Hunter-Reay, 11 behind Dixon.
Not to worry just yet though, the Kiwi just needs to finish ahead of him to take the championship.
The yellow flag has seen Rossi come roaring back though! He's up to 11th now, just 10 seconds behind the leading pair. Dixon around 0.8 seconds shy of Hunter-Reay.
Dixon now less than a second behind Hunter-Reay! Will this be where the Kiwi makes his move? He'll have to wait for the end of the yellow flag of course, but that shouldn't be too far away.
Rossi now under 30 seconds back from Dixon. He'll still have a lot to do, but don't write off his title shot just yet.
Yellow flag and Rossi can make up some ground on Dixon! Graham Rahal has crashed out.
Hunter-Reay and Dixon lose the top spots temporarily with their second pit stops. Both looking to keep their tyres fresh going into the second half of this race.
The pair are quickly back to the front of the grid though. Meanwhile, Rossi has moved up into 12th spot, still around 48 seconds back of Dixon though.
Dixon keeping pace with Hunter-Reay, doing enough to keep himself in pole position for the championship. The Kiwi is still second, but 12s ahead of third.
Dixon and Hunter-Reay now pulling clear of the chasing pack, with Simon Pagenaud over 11 seconds behind the leader. Dixon 2.5s behind.
Dixon now back into second, with Hunter-Reay's lead cut to less than 2s. Rossi lingering down in 23rd, 42 seconds back from the leader.
Hunter-Reay and Dixon now in the pit. Tyre change for the Kiwi as Josef Newgarden takes the lead. It's probably worth mentioning that should both Dixon and Rossi fail to finish, then Newgarden and Will Power will move into title contention.
Power hits the front as Dixon re-enters, he's now down to fourth, Hunter-Reay in third.
The first pit stops of the race have come about, but the leading group hold fire for now. Dixon just under four seconds back from Hunter-Reay.
Dixon nearly three seconds behind Hunter-Reay, but Rossi is at the back by over a minute. Advantage Dixon.
Rossi re-enters the fray, but he's at the back of the grid. Dixon still in second, Hunter-Reay leads.
Great news for Dixon - Rossi suffers wing damage and is under some early pressure, can he come back? Rossi smacked into Marco Andretti at the start, Dixon comfortable in second.
After 16 races, Kiwi driver Scott Dixon is within touching distance of his fifth IndyCar title, with today's season finale in Sonoma seemingly just a formality for the Manurewa native.
With three wins and eight podiums this season, Dixon holds a 29-point advantage over his next closest competitor, USA's Alexander Rossi.
Dixon effectively just needs to finish higher that Rossi to seal the title.
The Kiwi was leading the way to a pole position in qualifying - in what would have been his first of the season - before being pipped by American Ryan Hunter-Reay.
Dixon will instead line up in second spot, with rival Rossi having to settle for sixth.