Viciedo's one-out blast deep into the left-field seats off Kameron Loe (1-1) handed the Chisox the rubber match of their three-game set against Seattle.
Closer Addison Reed (1-0) was credited with the win after working through a touchy top of the 10th, during which he struck out Michael Morse with runners on first and second to end the inning.
Kendrys Morales went 3-for-4 with a bases-empty blast and Morse supplied a two-run shot for Mariners.
'SNL': 'Anchorman 2' cast, One Direction sing 'Afternoon Delight' [VIDEO]
Trader Joe's: Car crashes into Long Island store, injuring 11