Kevin Martin heads into the playoffs at The National boasting a 5-0 round-robin record. ((Andrew Vaughan/Canadian Press))

Kevin Martin and Jeff Stoughton finished with unblemished 5-0 records after winning their respective round-robin finales Friday afternoon at The National in Quebec City.

Heavyweight Glenn Howard was eliminated from playoff contention after being upset earlier in the day.

Martin, the two-time defending champion from Edmonton, defeated winless Chinese skip Fengchun Wang 6-3 in the eighth of nine draws at the Grand Slam of Curling tournament.

"It was a strong game," Martin said. "Especially the first four ends.

"They were in a lot of trouble early and we made a lot of the draws to the front button and to the front four."

Martin will face Martin Ferland of Trois-Rivieres, Que., in Saturday's quarter-final.

CBC Sports will broadcast Saturday's quarter-finals (CBC,, 11 a.m. ET) and semifinals (Bold,, 6 p.m. ET), and Sunday's championship final (CBC,, 12 p.m. ET).

Winnipeg's Stoughton is the only other undefeated skip after edging Joel Jordison of Moose Jaw, Sask., 4-3.

"Your expectations are that you want to win every game," Stoughton said. "So far it's going well and if we can string together a couple tomorrow and one on Sunday that would be awesome."

Stoughton will take on Edmonton's Randy Ferbey in the next round.

Ferland upset Ferbey 6-3, and Greg McAulay of Richmond, B.C., clipped Jean-Michel Menard of Quebec City 7-6 in Draw 8.

Brad Gushue of St. John's ran his record to 4-1 by beating Pat Simmons of Davidson, Sask., 3-2.

Gushue takes on Mike McEwen of Winnipeg, also 4-1, in the quarters. McEwen nipped Halifax's Shawn Adams 4-3 in the ninth draw.

The fourth quarter pits Toronto's Wayne Middaugh and Kerry Burtnyk of Winnipeg.

Howard, the winner of the season-opening Masters of Curling ended up 1-4. He was stunned 6-0 by Adams on Friday morning and then topped 6-5 by Middaugh in the final draw.

Middaugh and Burtnyk are both 4-1.

Burtnyk finished the preliminary round on a winning note by downing American Jason Larway 7-3.

With files from the Canadian Press