Australia's Will Power has rallied from 18th to finish fourth as Mexico's Pato O'Ward won the Indycar race in Birmingham, Alabama, breaking Team Penske's stanglehold on races this season.

O'Ward used a strong outside pass of pole-sitter Rinus VeeKay after both pitted for fresh tyres to take the lead then drive away for the victory from defending series champion Alev Palou of Spain and Dutchman VeeKay.

Former Supercars champion Scott McLaughlin then two-time winner American Josef Newgarden had claimed the first three races of the season for the Penske outfit.

But at Barber Motorsports Park on Sunday, Power was the first of the Penske drivers as he just missed the podium, with McLaughlin finishing sixth and Newgarden back in 14th.

Chip Gnassi racing's Palou's second placing was enough to put him on top of the driver standings with McLaughlin second, Newgarden third, Power fourth and O'Ward jumping from ninth to fifth.

There were late-race fireworks between fellow Honda drivers Graham Rahal and Romain Grosjean as the two raced for position, and an irate Rahal screamed over his radio "that guys a punk! He hit me on purpose."

An animated Rahal was seen after smacking his arm into Grosjean teammate Alexander Rossi to demonstrate Grosjean hitting Rahal's car.

"We touched a couple of times, but it was good racing," said Grosjean, who denied hitting Rahal on purpose. "No. No. No. It's IndyCar, wheel-to-wheel action."

IndyCar is off next weekend and most of the drivers are headed to Miami for Formula One's debut race on Sunday.

The series returns to action May 14 on the road course at Indianapolis Motor Speedway. VeeKay is the defending race winner.