Dayton Beach, Fla. ? Dale Earnhardt Jr. pushed the throttle to the floor. He whipped his shiny, red car to the outside, zipped past some slower competition and put himself right back in the running.

For 36th place.

Junior had one of the fastest cars Sunday at the Daytona 500. He was the favorite — not only in the minds of the experts, but in the hearts of the fans. He was going for an unprecedented sweep of four races at Dayonta.

But his alternator failed, and, alas, Earnhardt got another dose of a lesson his dad learned so many times at this track and every great driver in this sport has always known:

“The fastest car doesn’t always win,” said his crew chief, Tony Eury Sr.

Earnhardt again was star-crossed at Daytona — the scene of some of his family’s greatest triumphs and, of course, the ultimate tragedy: his father’s death.

Despondent after finishing 36th in a 43-car race he could have won, Earnhardt waited several hours to offer comment (and even then, only through a spokesman).

“It’s really heartbreaking to do so well and then have something like that go wrong,” Earnhardt said. “We know that this kind of thing happens to champions.”

But there were no championships to celebrate on this day. Just a lot of rain and a harsh reminder of what might have been in a race that was shortened to 109 laps.

When NASCAR officials called the race, Earnhardt’s teammate, Michael Waltrip, won his second Daytona 500 victory in three years.

Junior now is 0-for-4 in NASCAR’s biggest race — nowhere near the 0-for-20 string his father went through before finally winning in 1998, but frustrating nonetheless.

“That’s why it took Dale Earnhardt (20) years to win,” Eury said. “Sometimes, it’s just a $2 part.”