Takuma Sato has snatched an IndyCar victory at Portland International Raceway but Australian Will Power’s title hopes were dented by crashing out.

It is the third IndyCar victory for the Rahal Letterman Lanigan Racing driver and first since he won the Indianapolis 500 last season.

Power went off the course and crashed into a tyre barrier right after making a pit stop. He was battling a mechanical issue the entire race and lost the lead eight laps in when his car seemed to stall.

He is one of four drivers, along with Team Penske teammate Josef Newgarden, still racing for the IndyCar championship.

Meanwhile, Scott Dixon somehow salvaged his title run with an improbable comeback to finish fifth.

The four-times series champion put together the kind of drive that may define his season. He started 11th, was collected in an opening-lap crash, penalised for speeding on pit road and twice drove through the field from 20th.

Chip Ganassi Racing were forced to change their strategy several times and caution flags helped Dixon cycle ahead of the other championship contenders.

He moves on to the season’s final race next weekend with a 29-point over Alexander Rossi, who finished eighth on Sunday and lost three points to Dixon.

“Huge day for the team, feels like a win for us,” Dixon said.

Ryan Hunter-Reay nearly caught Sato over the final two laps but wound up second. Sebastien Bourdais, the last winner of an open wheel race at Portland in 2007, was third.