David Letterman had a new No1 on Sunday, on his personal Top 10 list of reasons he loves the Indianapolis 500.

The freshly retired Late Show host was all grins as his IndyCar team paid tribute by putting a gap-toothed, smiling caricature of his face and #thanksdave on driver Oriol Servia’s yellow car for the big race.

“With everything that’s happened, it’s the highlight of my career,” Letterman said. “It’s crazy it’s the Indianapolis 500. Regrettably my face, but also my name on that car. It’s just delightful.”

Letterman was dressed in a red shirt with a race sponsor “Steak ’n Shake” logo. He promised Servia he would buy the burgers for an Indy win. He would have to wash it down with a swig of milk.

It was easy to find the Rahal Letterman Racing spot in the Indianapolis Motor Speedway paddock: there was a red “Late Show with David Letterman” sign and the same grinning caricature that was featured on Servia’s car. Team members wore gray T-shirts with their own “Top 10” list of reasons they love Letterman. Among them: “cries on the parade lap”.

Letterman was born and raised in Indianapolis, spending his younger years in the Broad Ripple section of town. He went to Ball State college in Muncie, Indiana, and early in his career served as a pit reporter for ABC.

Letterman got into team ownership in the 1990s with former Indy 500 champion Bobby Rahal, and businessman Mike Lanigan came aboard to form what is now Rahal Letterman Lanigan Racing. Letterman struck a friendship with Rahal after the retired driver appeared on his show after winning the 1986 Indy 500.

Letterman could have filled an Indy 500 starting grid with all the series drivers he had on the show. Graham and Bobby Rahal were guests on The Late Show and the Indy 500 champion usually brought along the Borg-Warner Trophy.

“I’m just really pissed off because he finished this week,” Servia joked. “He couldn’t wait until next week? Because usually the winner goes to his show.”

Letterman was relaxed as he strolled through Indianapolis Motor Speedway, even inviting one fan over a barrier to sign autographs.

“Are you nervous?” Servia asked.

“No, I won’t be nervous until they start ’em up and then I just get crazy nervous,” Letterman said.

If Letterman acted as nervous as a new father, it’s because he is: not wanting to get left out of the father-son bonding of the Rahals, Letterman claimed Servia as his own offspring.

“Yes, I sent away to one of those genetic testing places where they do the swab and it turns out he is in fact my son,” Letterman cracked. “Bobby and Graham are father and son. Oriol and I are the same.”

Letterman ended his 33-year career as a late-night television host on Wednesday. He presided over 6,028 broadcasts on CBS and NBC, making Top 10 lists and ironic humor staples of television comedy. Letterman joked that he needed “some kind of intravenous medication” to recover from the grind of the final weeks of his show.

“Then the next day you feel a little bit better, and the next day you feel a little bit better,” he said. “Now here we are. This is the pressure-cooker. Of course, everybody wants to win. Everybody wants to win every year. But I really want to win this race.”

Letterman’s team won the race in 2004 with Buddy Rice. “He said, ‘I haven’t had a drink in 30 years and I feel like I’m drunk,’” Bobby Rahal said.

Letterman said he would watch the race from pit lane. At least he could find a seat, unlike the ones that were stripped from the Ed Sullivan Theater. Parts of Letterman’s set from his show’s home were quickly dumped in the trash and scooped by fans.

“Not only did they take the set and tear it up, they took all the seats out of the theater two days later,” Letterman said. “What that does is remind you that it’s show business. It’s just show business. Thirty-three years, what do I care. Let them take the seats out, let them do anything they want. I wish Stephen Colbert nothing but the best.”