Jaso rapped a two-out single in the sixth inning that broke a 3-3 tie and gave Seattle its longest winning streak since they won eight straight in 2007.
Eric Thames tied the game in the fifth with a two-run homer for the Mariners. Dustin Ackley had Seattle's other RBI.
Blake Beaven (7-6) earned the win, allowing three runs on seven hits over 7 2/3 innings. Tom Wilhelmsen pitched the ninth for his 15th save.
Carlos Villanueva (6-1) took the loss for the Blue Jays, who have dropped four consecutive games. Villanueva lasted six innings, giving up four runs on seven hits.
Reindeer recovered after escaping from Santa during lighting ceremony
Ukrainian protestors topple Lenin statue [VIDEO]