SAO PAULO — IndyCar officials added grooves to fix a slick straightaway in the season-opening Sao Paulo Indy 300 after drivers complained of loosing grip during testing Saturday and qualifying had to be postponed.

The work was done overnight and most drivers approved of the changes after a 15-minute practice session early Sunday to test the new surface at the 2.6-mile Anhembi temporary street circuit.

"It worked well, it's not a problem anymore," Brazilian rookie Ana Beatriz said. "There is enough grip there now."

Qualifying will take place the same day of the race for the first time in IndyCar Series history.

Drivers complained on Saturday that they were not able to fully accelerate without losing control at the straight. They said it was like driving on ice.

It was extremely dusty where the grooves were added, but drivers clearly had a lot more grip and lap times were significantly lower.

Cars were sliding and slipping throughout the straight on Saturday and several drivers crashed there in practice.

The straight goes through a stadium-like Sambadrome that stretches for about a third of a mile and is the only part of the track paved with concrete instead of asphalt. It is where Sunday's 75-lap race is scheduled to start and finish.

The surface is usually painted for the traditional Carnival parades at the Sambadrome, but it remained slippery even though organizers removed the paint ahead of the race.

The straight is the series' longest ever at just short of a mile.

Organizers had three months to set up the track following the announcement that the IndyCar Series would be coming to Brazil for the first time since the CART series raced in the Latin American country from 1996 to 2000.