Three titles are on the line in Saturday’s heavyweight bout, according to Youngstown Vindicator. Wladimir Klitschko has been in the ring with Tony Thompson, though he doesn’t remember it. Considering what happened afterward, who could blame him?

Thompson sparred with Klitschko before the bout against Corrie Sanders in 2003 that nearly finished the Ukrainian’s career. Now Thompson would like to be more directly involved with a defeat of Klitschko when he fights for the champ’s IBF, WBO and IBO heavyweight titles in Hamburg Saturday.

“I can’t remember that at all anymore,” said Klitschko, who had to call former trainer Fritz Smudek to confirm that Thompson was a sparring partner. “But it’s OK, I’ve learned not to underestimate anyone anymore.”

The hard-hitting Sanders appeared to destroy the myth of the next big thing by sending Klitschko, who came into the fight with a 40-1 record, to the canvas four times to win by knockout in the second round.

Klitschko (50-3, 44 knockouts) bounced back to win eight straight fights and be widely considered as the division’s best fighter, but Thompson (31-1, 19 KOs) says the Ukrainian’s time has passed.

“It won’t help him if he remembered me,” Thompson said. “I’m a hundred times better since that time. But I saw the best of him back then.”

The college-educated Klitschko remains privileged in many ways. The son of a former high-ranking Soviet Union officer has money pouring in through lucrative advertising deals in Ukraine and Germany.

That’s not the case for the 36-year-old Thompson, who grew up in the projects with his father in prison.

Klitschko had promoters lined up to sign him after winning the super heavyweight gold medal at the 1996 Atlanta Olympics.

Thompson still needs money, telling reporters he has to feed his seven children and fix a broken dishwasher and air conditioner back home in Washington, D.C.

“I have a family to take care of — I can’t do that unless I beat this guy,” Thompson said. “Then, I will get known in the United States and the big money will come by itself.”

Thompson worked his way into a mandatory shot with a fifth-round stoppage of Germany’s Luan Krasniqi in July.

Although a big underdog for the fight, the left-handed Thompson is 6 feet, 5 inches tall — a near match for the 6-foot-7 Klitschko. His long arms could help deflect the Ukrainian’s powerful left jab.

“I saw his strong performance against Krasniqi,” Klitschko said. “And this is his big night.”