Champion again: Kylie Masse repeats as 100m backstroke gold medallist at swimming worlds

Canada's Kylie Masse made it back-to-back world titles in the women's 100-metre backstroke, clocking 58.60 seconds at the world aquatics championships in Gwangju, South Korea, on Tuesday.

Australia's Minna Atherton held the lead midway through the race but a composed Masse, who was fourth at the turn, came on strong in the final 50 metres, holding her stroke together for the victory at Nambu University Municipal Aquatics Center.

WATCH | Kylie Masse wins back-to-back backstroke world titles:

Masse is the first Canadian swimmer to defend a world title and joins the late Victor Davis as the only Canadian swimmers to capture two gold medals at the event.

"It's such a great feeling," Masse told CBC Sports. "After the semis I looked at my race video and saw some areas I could improve on, so I tried to execute that and I think that helped coming off the wall with momentum and speed that carried me to the finish."

Atherton placed second in 58.85 while Olivia Smoliga of the United States was third in 58.91.

"It is so hard to do that," CBC Sports swim analyst Byron MacDonald said of repeating as world champion. "I believe only two other swimmers on the planet are going to be able to claim that after these worlds are over. Truly a great performance."

Does this make Masse the odds-on favourite to win gold at next summer's Olympics in Tokyo?

"No," said MacDonald. "Will she be one of the favourites? Absolutely, yes. The field is so close … tenths of seconds that anything can happen in an Olympic year. Remember, [Canada's] Penny [Oleksiak] did not even make worlds [in 2015 before winning four medals at the 2016 Olympics] so people can come from nowhere."

WATCH | Masse on her mindset late in the 100m backstroke:

Masse a 'true champion'

Canada coach John Atkinson was impressed with Masse's ability to perform under pressure.

"When you come into any major championships and Games as defending champion, there's a whole different level of expectation on the athlete," he said. "I think Kylie handled herself tremendously. "Her experience came through over that second 50 [metres], and she is a true champion."

Taylor Ruck of Kelowna, B.C., appeared to be in medal contention but faded over the final 25 metres, finishing fourth in 58.96. Ruck, who set a personal-best time of 58.55 on April 3 at the Canadian trials, had withdrawn from the 200 freestyle hours earlier to concentrate on other events in Gwanju.

"Taylor was struggling a bit earlier this summer and is just starting to get back to top form," says MacDonald, who coaches at the University of Toronto. "She was only marginally off her best time today. She is a fantastic athlete and will be a medal threat many times over in her career."

American Kathleen Baker, who ended Masse's world-record reign at 368 days last year, was sixth in 59.56. The 22-year-old from Winston-Salem, N.C., arrived in South Korea having not competed since March due to a rib injury, and recently pulled out of the 200 individual medley at worlds to focus on the backstroke.

Masse, 23, entered Tuesday's race determined to take back the world record Baker snatched from the native of LaSalle, Ont., after clocking 58-flat at the U.S. swimming championships last July. A shocked Masse won gold two years ago at worlds with a then-world record time of 58.10.

Commonwealth gold

Masse was in Japan preparing for the Pan Pacific Championships last August when Baker broke her record.

The U of T swimmer went on to capture gold in 58.61 with Baker clocking 58.83 for bronze. Earlier that summer, Masse stood atop the podium at the Commonwealth Games in Australia and came closest to taking back the world mark earlier this year with a 58.16 clocking at Canadian trials.

Masse's performance gave Canada its second gold of these worlds after Maggie MacNeil of London, Ont., surprised many with her victory in Monday's 100 butterfly.

Ruck, 19, is making her debut at worlds after recently completing her first year at Stanford University in California.

WATCH | Taylor Ruck 'having a blast' in Gwangju:

Her rise began at the 2016 Olympics in Rio when she helped Canada's freestyle relay team to a pair of bronze medals.

Two years later at the Commonwealth Games, Ruck's record eight-medal haul included gold in the 200 freestyle where she set a meet record, and silver in the 50 freestyle where she set a national record. Later in the summer, Ruck became the first Canadian to win five individual medals at a single Pan Pacific Championships.

Oleksiak advances to 200m freestyle final

Penny Oleksiak of Toronto qualified seventh for Wednesday's women's 200 freestyle final in a personal-best time of one minute 56.41 seconds.

'"I felt really good going out but I let it get a little bit away from me,'' said Oleksiak, who led for the opening 150 metres. "I've been trying to work on the front half of all of my races. I just need to get more confident with that."

WATCH | Penny Oleksiak sets PB in 200m freestyle semifinals:

The 19-year-old helped Canada to a bronze medal in the women's 4x100 relay along with Kayla Sanchez, Maggie MacNeil and Taylor Ruck to open these world championships on Sunday.

Nearly three years on, Oleksiak still has trouble comprehending the gravity of her 2016 Olympic accomplishments when she won gold in the 100 freestyle, silver in 100 butterfly and relay bronze in the women's 4x100 and 4x200.

"I think it's just I don't want to disappoint Canada, which sounds weird and sounds really cheesy," she told CBC Sports recently. "But going into the next Olympics, I don't want people to be disappointed in me if I don't do as well as they think I'm going to do."

In the men's 200 semifinals Tuesday, Mack Darragh of Oakville, Ont., was 14th and did not advance.

Sun Yang again shunned at podium

Sun Yang was in the middle of controversy at the world swimming championships again. Only this time, it wasn't his doing.

Sun won the 200-metre freestyle on Tuesday after Danas Rapsys of Lithuania finished first and got disqualified for an apparent false start.

The Chinese star touched second, but got elevated after Rapsys had already celebrated in the pool.

Sun appeared surprised, clasping his hands to his face, but quickly sat on the lane rope and raised both arms in the air as a mix of cheers and boos rang out.

Once again, Sun got shunned by a competitor on the medals podium. Duncan Scott of Britain kept his hands behind his back and refused to shake Sun's hand, standing off on his own while the other medallists joined Sun to pose for photographers.

WATCH | Crowd applauds Duncan Scott's decision to stay off podium:

Sun, who served a three-month doping ban in 2014, is being allowed by FINA to compete in Gwangju ahead of a Court for Arbitration in Sport hearing in September that threatens Sun's career.

Sun has been accused of smashing vials of his blood with a hammer during a clash last year with testers, and faces a lifetime ban if found guilty.

After Sun won the 400 free, silver medallist Mack Horton of Australia refused to step on the podium or acknowledge Sun during the medals ceremony. FINA, swimming's governing body, sent warning letters to Swimming Australia and Horton for his actions.

WATCH | Mack Horton refuses to share the podium with Sun Yang:

Elsewhere on Tuesday:

• Without three-time defending champion Katie Ledecky of the United States in the field, Simona Quadarella of Italy won the 1,500 freestyle in 15:40.89 — well off Ledecky's world record of 15:20.48. Earlier Tuesday, the American star withdrew from the final because of undisclosed illness. Ledecky also dropped out of the 200 freestyle heats. Sarah Kohler of Germany earned silver and Wang Jianjiahe of China took bronze.

• Olympic and defending world champion Ryan Murphy was upset in the men's 100 backstroke. Xu Jiayu of China won in 52.43 seconds. Evgeny Rylov of Russia took silver and Mitch Larkin of Australia got bronze.