Middaugh (4-0) scored once in both the seventh and eighth ends to tie the score 5-5 before securing the victory over Nedohin in Draw 8 play.
Middaugh sits tied atop the standings with Calgary's Shannon Kleibrink, who was idle.
Meanwhile, Saskatoon's Stephanie Lawton (3-1) scored two in the eighth end to defeat Winnipeg's Chelsea Carey (2-2).
Ottawa's Rachel Homan improved to 3-1 with a 9-2 win over Edmonton's Valerie Sweeting, while Kelly Scott (3-1) of Kelowna, B.C., doubled up Winnipeg's Kaitlyn Lawes (2-2) by a count of 6-3.
In other action, Krista McCarville (1-2) of Thunder Bay, Ont., doubled up Halifax's Heather Smith-Dacey (0-3) by the same 6-3 scoreline, Cassie Potter (1-2) defeated fellow American Allison Pottinger (0-3) 5-3, and Lisa Eyamie (1-2) of High River, Alta., got past Calgary's Crystal Webster (0-3) 8-7.