Australia’s Alex Leapai is on course for a shot at WBO and WBA heavyweight world champion Wladimir Klitschko after upsetting No.1 contender Denis Boytsov.

Australia’s Alex “The Lionheart” Leapai is on track for a showdown with WBO and WBA heavyweight champion Wladimir Klitschko after a boilover win over previously unbeaten WBO No.1 ranked contender Denis Boytsov in Germany.

The Samoa-born Queensland-based slugger knocked Russian Boytsov (33-1, 26 KOs) down twice on the way to earning a unanimous 10-round points victory in Bamberg, Germany early Sunday AEDT.

Two judges scored it 96-92 and their colleague 98-90, as Leapai retained the WBO Asia Pacific title and recorded the most significant win of his career.

Leapai revealed after the fight not everything had gone his way.

“In round seven I tore my calf muscle and I had to fight on,” Leapai told Fox Sports News.

“Broken hand, torn calf muscle, they don’t call me The Lionheart for nothing.

“I wasn’t going to let Australia down, I wasn’t going to let Samoa down.

“I’m pretty sure all of Australia will be backing me now.”

Having upset the leading contender, Leapai is now in the mix for a fight with WBO and WBA champion Klitschko.

He would start a massive underdog against 37-year-Klitschko, who has an imposing 61-3 record with 51 KOs and a 19-fight winning streak stretching back nine years.

“I was the biggest underdog here in Germany,” Leapai said.

“They say you can’t win in Germany, you’ve got to knock them out, but if I can beat Boytsov, I can beat anybody.”

It was a fifth straight victory for Leapai (30-4-3, 24 KOs), who has lost just one of his last 23 fights since 2008.

At 34, seven years older than Boytsov, Leapai knocked the younger man down in both the seventh and the ninth and pummelled his opponent in the 10th.

“When the fight started he started going backwards when he normally always comes forward,” Leapai said.

“I pushed him back the whole 10 rounds. He felt my power and it probably scared him.”

Leapai ended up on the floor on a couple of occasions but they were ruled slips, while Boytsov was warned by the referee on a number of occasions for foul tactics.