Rebecca Marino's oar pierces the calm waters of the Fraser River on a crisp spring morning.

Stroke after stroke dips below the glistening surface as she helps her University of British Columbia rowing crew glide forward.

The setting just south of Vancouver is a long way from the professional tennis career and crippling depression that dominated Marino's life until three years ago.

After so much heartache, she knows this is where she belongs.

"It's been a while since I've had a bad day," Marino said after a recent practice. "I honestly can say I'm a different person. That's why I stepped away from tennis — to find myself and work on my mental and physical well-being.

"And here I am."

Retirement at 22

The former No. 38 women's player in the world, who waged a memorable battle with Venus Williams in the second round of the 2010 U.S. Open and made the final of another WTA tournament the following season, announced she was leaving tennis in 2013 at age 22.

There were days when the depression was so bad Marino couldn't get out of bed. She had taken a seven-month break the previous year to finally seek treatment, but when she returned the passion was gone for a player who had tumbled 380 spots in the rankings when she retired.

"I'm pretty comfortable with how things went," said Marino, who added there's no plan to ever return to the pro ranks. "I can't really look back and wonder: 'What if?' I'm in a really great place.

"I'm doing things I love now. I wouldn't change it."

Former professional tennis player Rebecca Marino, centre, practices with her University of British Columbia rowing teammates in Richmond, B.C., on Friday April 15, 2016. (Darryl Dyck/The Canadian Press)

But while she was done with the nomadic life on tour she said contributed to her depression, the competitive juices still flowed.

Marino was focusing on studying English literature at UBC and teaching kids at the university's tennis centre when women's rowing head coach Craig Pond saw an opportunity. Rowing is often a late-entry sport that attracts athletes from other disciplines, and Marino's six-foot frame with long limbs made her a prime candidate.

"She fits the bill for a rower," said Pond. "We took it slow and didn't force the sport on her. I knew she was going to be a very effective member of the team if she was prepared to commit.

"I wanted to make sure she was enjoying the process."

'Avoided rowing for a long time'

And while the 25-year-old from Vancouver tried to fight it for most of her life, rowing is part of the family business. Marino's uncle, George Hungerford, won gold for Canada at the 1964 Olympics, and her brother competed at the University of California.

"I actually avoided rowing for a long time," Marino said with a laugh. "I just thought: 'I'm never going to wake up at 4 a.m., come to practice, go until I almost want to puke.'

"Who would want to do that?"

But she was convinced to finally give it a shot and was hooked. Marino started as a novice rower at the beginning of the school year, quickly moved up into UBC's second boat and is expected to challenge for a spot with the varsity women's eight this fall.

"The neat thing she's brought from tennis is she puts a lot of pressure on herself," said Pond. "Provided we harness that correctly, that's a really valuable asset."

After dedicating her life to an individual sport where success or failure rested solely on her shoulders, Marino said joining a team environment has been a welcome change.

"There's a camaraderie," she said. "You really bond together as a crew."

'It's really inspiring'

UBC teammate Emmie Page said having Marino on board has impacted the group in many ways.

"Trying to imagine her playing [tennis] at that level is absolutely insane," said Page. "I know the whole team loves to talk to her about it because it's really inspiring.

"She's helped the integration of the team. She's older than many of the incoming athletes, but she brings us all together."

When the conversation shifts to her struggle with depression, Marino said she's pleased that mental health issues are getting more attention than when she felt isolated on the WTA tour, often far away from her family and support network.

"I think it's just part of the process of where we're going in society," she said. "I'm just one of those voices helping create awareness."

Marino also cited cyberbullying she received as one of the difficult aspects of her tennis career and said she still shies away from social media.

"There's some hesitation," she said. "The anonymity of the Internet is really dangerous."

But getting to stay in the sport by teaching kids has also helped her fall back in love with the game.

"It's fun to see them learning at the beginning where I was," said Marino. "That's where I get the benefit from coaching.

"That's where I win."

Some of her students have made the connection with Marino's past — there's a picture of her on the wall at UBC — although it's not something she broadcasts.

"It's up to them," she said. "If it eventually clicks and they find out I played all those tournaments and I played Venus, awesome."

Marino doesn't like to watch tennis on TV — "I get a little too competitive" — but she has a new path in rowing that Pond said could one day lead her as far as the national team.

"She's got the background in sport and she understands the drive it takes to achieve those lofty goals," said the coach. "I think she can get there."

One stroke at a time.