EDMONTON -- Their's is a partnership forged over the better part of a decade of some of the highest of highs and most gut-wrenching lows.

And when Melissa Bishop crouches at the start line of the 800-metre race in Rio, she won't be alone.

The man she lovingly calls "Big Dawg" -- her coach Dennis Fairall -- is battling progressive supranuclear palsy, a degenerative condition that has no cure. They'll be together in Rio, for a race that means so much more than an Olympic medal.

"It's a run for Dennis," Bishop said Saturday, with a sad smile. "This is why I'm doing this. In 2012 when he was ill with cancer (of the larynx), I was doing this for Dennis. And now we've grown so much in these past four years, this is really for Dennis.

"Because I don't know. . . I don't know how much farther we'll go with this."

The 27-year-old from Eganville, Ont., will head to Rio as one of Canada's brightest stars after her thrilling silver medal performance at last summer's world championships.

Bishop must earn her spot first, of course, but needs only a top-three finish Sunday at the Olympic trials.

Saturday, wearing her blonde hair pulled back, a grey and black singlet and shorts, and a dark tan left over from warm-weather training, Bishop cruised to an easy semifinal win. She kicked to pull away form her competitors over the final 200 metres to cross in a relaxed two minutes 5.8 seconds.

"I was impressed by the way she held off the challenges," said Fairall, a wizard at race tactics.

A coaching icon, Fairall has been named either CIS or OUA coach of the year 65 times in track and field and cross-country. His teams have won 71 CIS and OUA titles, including 20 CIS national track titles.

The 63-year-old was diagnosed almost three years ago with PSP, which is the deterioration of cells in the brain that control body movement and thinking. Survival from onset averages seven years.

"Big Dawg" is actually about Bishop's height -- five foot seven -- and he has a full head of white hair that's usually stuffed under a baseball cap.

He has good days and bad days. Stairs are difficult to negotiate, and the nights, when he's tired, are particularly tough.

He's at his best at the track. This week's Olympic trials at Foote Field, like any national championship, is like a giant track family reunion with coaches and athletes pausing to say hi and catch up.

"He's holding his own. We get through. Gotta get through that bucket list," his wife Janet said, with a smile.

Bishop credits Fairall with a career that saw them team up in 2008 when she arrived at the Windsor, Ont., and truly took off the past couple of seasons.

He guided her through a tough 2014 that saw her lose both her grandfathers, including one on the day of her 800 final at the Commonwealth Games, and a young cousin in a car accident.

She bounced back with last year's outstanding season, shattering the Canadian record to run 1:57.52 for silver in Beijing.

Her meteoric rise has made her a household name, and landed her on giant Nike billboards -- which she calls "kind of cool, to see Canadian athletes get recognized."

Bishop's dad Doug said she wouldn't be where she is without Fairall.

"And he provided opportunities also, early on, he'd take the kids to Europe and let them race there, for the exposure," added her mom Alison. "And of course any teams that she's made he's been there with her. That's huge."

"They're a team, they're doing this together," she added. "Going to Rio, it's for both of them. She's just so glad that he can with her, because doing track without him is probably not in her imagination."

Athletics Canada is providing accommodations in Rio for Fairall and his wife, who's travelled to dozens of countries together in their 45 years together.

There, Fairall will draw up the most important race strategies of Bishop's career.

Post-Rio, the two will continue to take life as it comes.

"I hope he'll see me through until I'm ready to retire," Bishop said. "As long as he can put words on paper, I think we'll be able to. He's been one of the biggest supports for me through all of this, above anybody else.

"He's been . . . he's been a big support."