CONCORD, N.C. (AP) _ Rick Mast struggled most of the season trying to get competitive. Then, after he finally did get his Pontiac Grand Prix in the running, new problems arose.

``It's gratifying to finally run well, but the problem with that is, like Sunday at (North) Wilkesboro, the first half of the race I felt like we had a dominant car,'' Mast explained. ``I was sitting there trying to figure out how we could win, what to do the last couple of hundred laps to win the race.

``I kind of did some wrong things with the car, and we got it off a little the last 100 laps,'' he added. ``Instead of being real happy for finishing sixth, I'm a little disappointed because we didn't have a shot at winning.''

For Mast, having a shot at winning is a feeling he hasn't had too many times during his eight-year Winston Cup career. His best finish, second place, came at Rockingham in the fall of 1994, and there have been only seven top-five finishes in all.

But the 39-year-old Virginian is riding a hot streak heading into Sunday's UAW-GM Quality 500 at Charlotte Motor Speedway.

His last three races have produced finishes of sixth, fourth and sixth after only two top-10 finishes _ a ninth and a 10th _ in the first 24 events this season.

Adding to the excitement, his wife, Sharon, gave birth to twin daughters, the couple's first children, Wednesday night.

``Everybody at home is fine and I feel great,'' Mast said. ``The team is on a roll. What we've done the last three races is what I've been saying and thinking we could do for a long time.

``The first half of the year we were hindered because we didn't have the right aerodynamics,'' added Mast, who did a considerable amount of offseason testing on the new Pontiacs. ``Now we've got that working.

``And Brad Thrower in the motor room, he came out with a new motor design for Indy (in August), and I'm telling you, I've got the best motors I've ever had.''

It might be a case of too little, too late for Mast, who will be ending his relationship with car-owner Richard Jackson at the end of the season, moving on to drive Fords next season for Butch Mock.

``It would be nice to leave these guys with a win or two,'' Mast said. ``I've been at this for a while and I want to win races. Top-10s and all that are neat. Top-fives are fine and neat. But I want to win.''

Mast says the 1 1/2-mile Charlotte oval could be just the perfect place for that first win.

``I've had some good runs here in the past,'' he said. ``The finishes again aren't indicative of that, but that seems to be my story the last two or three years. We run strong and then something happens and we finish bad.

``Now that we've had some decent finishes, maybe we're turning that around. Why not at Charlotte?''

In the unique schedule for the fall race at the Charlotte track, the 43-car lineup is already set and Friday was a day off for the Winston Cup drivers. Practice for the 500-mile race will resume Saturday.