McEwen (5-0) scored single points in the first three ends of the match, and added two more in the fifth for his second win of the day. The Winnipeg skip topped Steve Laycock (2-2) of Saskatoon 6-5 earlier on Friday.
Olympic gold medallist Brad Jacobs of Sault Ste. Marie, Ont., was eliminated after going 2-3 in the round robin. Jacobs started his day with a 5-2 win over South Korea's Soo-Hyuk Kim, but fell 8-1 to Oskar Eriksson of Sweden in the ninth draw.
Stoughton is 3-2 after losing his second match of the day, 6-4 to Edmonton's Kevin Martin (4-1).
Martin came from behind, scoring two points in the fifth end, and adding one each in the sixth and seventh for his second win. Martin beat Edmonton's Brendan Bottcher 8-2 earlier in Draw 8.
Glenn Howard of Coldwater, Ont., kept pace with Martin with a 4-1 record.
Howard scored three in the fifth end to beat Brier champion Kevin Koe of Calgary 8-4 in Draw 8, after edging Halifax's Mark Dacey 6-5 in the sixth draw.
Koe (3-2) won his first match of the day 8-4 over Switzerland's Pascal Hess (1-4).
Brad Gushue is 3-1 after dropping his eighth-draw matchup 8-1 to Eriksson (4-1). Gushue took a 10-5 win over Regina's Brock Virtue (0-5) in Draw 7.
Switzerland's Sven Michel is 5-0 after wins against Dacey and Hess. Niklas Edin of Sweden is 4-1 after beating Eriksson in Draw 6 but losing to Kim in the final draw of the night.