"This year we've been playing well in the round robins and the qualifying rounds but we get to the playoffs and we've been kind of stinking the bed," said the veteran.
He's also glad to be reunited with third Mark Nichols, who returned to his home province after the breakup of the Winnipeg rink led by Jeff Stoughton.
"It was something I missed over the last couple of years and no disrespect to the guys I played with," said Gushue.
"We got our lumps and bruises over the last 15 years playing and we've had the same experiences, so we're kind of on the same level."
"It feels great," agreed Nichols, both of the win and the renewed partnership.
"We started off slow this season. It always seemed like we had someone struggling."
They curled together from 1999 to 2011, including a Canadian Junior Championship in 2001 and an Olympic gold medal in 2006.
Some big shots set the stage but it was a well-swept draw for two in the seventh end that made the difference, letting Gushue come home with a cushion.
Earlier, it looked like he was sure of the prize after a big four in the fifth end broke open a close game.
But McEwen came back in six with a four of his own on a spectacular triple-raise takeout, after Gushue hogged his attempt at a final guard, that sent them to seven tied 6-6.
McEwen didn't even pretend he thought he had a good chance of making it.
"It's a bit of a hope," he said with a laugh.
"The difference when you're running such a high rock onto a second guard, the difference is an eighth of an inch (that) can sink you."
With his 8-6 cushion from seven, and a big hit that cleared McEwen from the house, Gushue ran McEwen out of rocks and they shook in eight.
They had blanked the first and McEwen stole one in the second. Gushue had a deuce in the third end to go ahead 2-1 and McEwen had to settle for a single in four to tie it up going into five.
Gushue took home $23,500 and 12 Rogers Cup points. McEwen had to settle for $14,500 and nine
McEwen has been hard to beat this season with four World Curling Tour wins and an overall record of 33-2 before Sunday.
McEwen demolished Olympic gold-medal winner Brad Jacobs 7-2 in five ends Saturday night to get to the final while Gushue needed an extra end to edge Toronto's John Epping 6-5.
McEwen's only loss during the week was to Calgary's John Morris, who took over Kevin Koe's Brier-winning rink after Koe struck out on his own with a new team. Gushue's only loss was to Manitoba's Jeff Stoughton.
Earlier, Valerie Sweeting of Edmonton claimed the women's title when she defeated Sweden's Margaretha Sigfridsson 5-4.
Her odds were tough when she lost her newest recruit just before the event and she made them longer when, once again, she let her clock run down, but this time Sweeting had a time out in her pocket.
"I wanted to take it (the time out) on my last so I'd have lots of time to throw," she said after the win, her first ever at a Slam. "Yesterday we almost ran out of time and we didn't have a time out."
It was a tight game but Swedish fourth stone Maria Prytz flashed on a couple of hits and Sigfridsson, who throws lead, said mistakes like that are costly.
"It went back and forth and we missed too many key shots," she said. "You can't afford that."
To get to the final, Sweeting had to knock off reigning Scotties champ Rachel Homan on Saturday night.
Cathy Overton-Clapham, who threw third stones for Sweeting, was a last minute recruit after Andrea Crawford unexpectedly left to return to her native New Brunswick. She only joined this year as a replacement for second Joanne Courtney, who joined Homan's rink.
"I did say seriously? I haven't thrown a rock in three weeks, are you sure you still want me?" said Overton-Clapham, third for current Olympic champ Jennifer Jones until she was dumped in favour of Kaitlyn Lawes in 2010.
She went on to successfully skip her own rink but most recently played third for the Crystal Webster rink in Calgary.
"She was so great, we learned so much from her this week," said Sweeting, who has already replaced Crawford with Lori Olson Johns, who played second for Calgary's Cheryl Bernard.
To get to the final Sigfridsson had to go through Jones, who beat her in the women's curling final to claim Olympic gold in Sochi.
With the win, Sweeting picked up $23,500 in cash and 12 Rogers Cup points and second place earned Sigfridsson $13,500.
Sigfridsson was down 4-2 in seven when Prytz at least partially made up for those flashes with a deuce on a long raise takeout to tie the game.
The eighth end was a nail biter down to the last rock as Sweeting tried to keep the house open so she could use the hammer and Sigfridsson capitalized on misses.
Sweeting had just 15 seconds left on her clock as she used her last time out to throw her last rock.
"We burnt a lot more earlier in the game than we needed to but it all worked out in the end."