CONCORD, N.C. (AP) — Rain has wreaked havoc with NASCAR's opening race for the second round of the playoffs.

All practice was canceled Saturday at Charlotte Motor Speedway, and the start of Sunday's race has already been moved up an hour to give NASCAR a bigger window to complete the 500-mile event.

It's not the Chamber of Commerce weekend that Charlotte officials had hoped for when they rearranged the schedule. This event has traditionally been held on Saturday nights but was washed out last year by Hurricane Matthew.

Held the next day, on a gorgeous Carolina afternoon, the race was one of the more competitive events of the season. Drivers felt that running in the afternoon improved the on-track product, and Charlotte officials adjusted by moving the event to Sunday.

Now, Hurricane Nate is expected to spoil the day.

The track had a different struggle Friday after it discovered it had not properly applied traction compound to the track. It required a second application in the turns, but not before it caused Dale Earnhardt Jr., Kyle Busch, Brad Keselowski and David Ragan to wiggle exiting Turn 4 and hit the wall during practice. Both Earnhardt and Busch had to move to backup cars.

Charlotte officials figured out that it had not applied enough of the PJ1 sticky substance in that turn, and drivers had asked about it after the dicey practice session.

"The stuff that they sprayed down, it has had a bad reaction to the sun or something that has made it really slick," Earnhardt said after Friday's accident. "Something has made it to where it doesn't have grip, it's the opposite."

Now the rain will wash some of the substance away, and with all practice canceled Saturday, drivers won't know what to expect when the race does begin. Earnhardt crashed in the opening moments of Friday practice, and said he'd avoid the top line of the track where the compound is until another driver demonstrates there's no danger.

Thins go watch at Charlotte:

GIBBS OUT FRONT: It was little surprise to see a pair of Toyotas sweep the front row in qualifying. The cars, though, weren't the usual suspects.

Denny Hamlin and Matt Kenseth gave Joe Gibbs Racing the top two starting spots for the race. The stronger Toyotas in qualifying this year had belonged to Martin Truex Jr. and Kyle Busch.

For Hamlin, the up-front starting spot is important to getting off to a good start in this round of the playoffs. He's lagging behind Truex, winner of the playoff opener at Chicago, and teammate Busch, winner the last two weeks.

"We're in that kind of a middle spot in the grid right now where we have some decent playoff points, but we're still 40 or so behind Truex and maybe 30 or so behind Kyle, and we can knock a big chunk out of that if we run up front in the first two stages," Hamlin said. "So we've got the starting spot to do it. We need to log all the points we can while we have the track position, and I'm glad we're starting off this round this way, and hopefully our car is good enough to stay there to get those points early on."

LIFE IS GOOD: Truex has been difficult to catch this season and leads the series with five wins, 19 stage victories and 59 playoff points. So he's had very little to complain about from his spot out front.

"It feels really good honestly," he said. "It's been a great season and you know it's been really cool to be kind of the guy to beat or to have the most stage wins, the most points, the most wins, all that stuff."

But Truex knows how quickly it can change. He dominated the first round of the playoffs last season, only to falter in the second round. He was eliminated at Talladega last year after winning two of the first three races of the playoffs.

"We're trying to just really stay focused and not really reminisce too much," he said. "I feel like our team is doing a great job of doing that. Staying focused, and we know where we want to go. Just try to — got to get there. It's going to be difficult, there's no doubt about it. But it does feel really good. It's been a lot of fun this year."

RAISED STAKES: Talladega is next on the calendar, and it's typically a race that can destroy a driver's championship chances. With that in mind, the remaining 12 drivers in the playoffs are determined to get strong finishes at Charlotte.

It means the racing at Charlotte should be aggressive, which Ryan Blaney believes has been the case through the first three playoff races.

"It's intense, for sure. From Lap 1. That's the way it's supposed to be. (It's) supposed to be 'on-go' from the drop of the green flag," Blaney said. "There shouldn't be any riding around. There is a lot more give in the regular season and there's not much of that in the postseason and that's good. That's how it should be and that's how I like racing."

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