Rockingham, N.C. ? Daytona 500 champion Dale Earnhardt Jr. is close to unbeatable in restrictor-plate races.

He’ll get a chance to show whether he’s truly a contender to win the Nextel Cup title as NASCAR shifts to North Carolina Speedway, a difficult track where Junior has struggled often.

In eight career top-series starts at the 1.017-mile oval, Earnhardt’s best finish was 13th, in November.

His Dale Earnhardt Inc. team has spent a considerable amount of time testing in preparation for the Subway 400, hoping the extra work will propel him to another victory.

“In the past, it was a track we struggled at,” he said. “It may be the only place we haven’t really conquered yet.”

Junior has proven to be a master at Daytona and Talladega Superspeedway — the two tracks that require horsepower-sapping restrictor plates — partly because of the time and energy DEI devotes to those facilities.

He won all three races he entered at Daytona last week and has nine career victories there.

But if Junior wants to be taken seriously as a championship contender, he needs to improve at the tracks he has never masked his disdain for.

That includes Rockingham, where the rough surface eats away at tires.

“Even though we devote a lot of effort and time to restrictor-plate tracks, Rockingham is a track we’ve emphasized as a place where we need to improve if we’re going to win a championship,” he said. “I used to come here with a bad attitude, and it seemed to set the tone for the whole team.

“I think it’s different now. If anything, winning the Daytona 500 gave us more confidence than we already had as a team, and that’s probably the one thing we lacked heading into Rockingham in the past.”

The entire complexion of Sunday’s race should be different from past years because of new, NASCAR-implemented aerodynamic rules that revolve around smaller rear spoilers and less downforce.