Kelly Slater beaten at Rip Curl Pro in last ride at Bells Beach as Aussies Ethan Ewing & Morgan Cibilic make quarter-finals

Kelly Slater has probably made his competitive swansong at storied Bells Beach after rising Hawaiian star Barron Mamiya sent the legendary American packing at the Rip Curl Pro.

The 11-time world champion is already looking forward to the next World Surf League event at Margaret River in mid-April, but only victory there would change his mind about retiring.

Slater was unable to find a way past Mamiya, who caught the best two waves in a low-scoring 11.37-10.10 round-of-32 victory on Saturday morning at Winkipop.

“It’s been fun. It’s likely it’s my last one. If I don’t win at Margarets this will be my last Bells,” the 52-year-old said.

“We’ll see what the future brings (but) I’ll enjoy Margarets for what it is.”

Mamiya admitted to a bout of nerves heading into the clash against the all-time great.

“I’ve never really beaten Kelly in a man-on-man heat so it was nice to finally get him on one before he finally retires, or whatever he does,” he said.

Slater fell on his final manoeuvre of what was shaping as his highest-scoring wave late in the heat, opening the door for Mamiya to pounce.

“My first wave of the heat, I really just blew,” said the Hawaiian.

“I don’t know what happened; I was a little nervous or something.

“I got way too much onto my front foot and started digging rail, and then I thought, ‘I’ve got to clean it up and get some waves’.”

Slater and retired Australian greats Mark Richards and Mick Fanning are the only men to have won four titles at Bells.

Mamiya was also gone by the end of the day after losing his round-of-16 clash to American Jake Marshall.

There were two rounds of the men’s competition completed on a long day at Winkipop, with Australians Ethan Ewing and Morgan Cibilic advancing to the quarter-finals.

Defending champion Ewing is the only former Bells winner still standing in the men’s competition after downing compatriot Liam O’Brien 15.77-14.33 in a high-quality encounter in the round of 16.

“It was actually really fun but these inconsistent heats and days are super-hard and super nerve-wracking because you just never know how many opportunities you’re going to get,” said Ewing, who will square off against American Cole Houshmand in the quarters.

“I just went into it trying to get a quick start and the 8.5 (point wave) was a good way to start off.”

Cibilic beat Ryan Callinan - both of whom hail from Newcastle - and will next take on South African Matthew McGillivray.

Jacob Willcox and local wildcard Tully Wylie were eliminated earlier on Saturday in the round of 32.

The women’s contest is already through to the last-eight stage, where teenaged wildcard Ellie Harrison is the only Australian still in the running.