With the Maple Leafs on a 5-on-3 power play, Rittich made a glove save on Tavares at 6:24 and Auston Matthews hit the post six seconds later.
"You get that type of opportunity, we have to find a way to capitalize," Tavares said. "I had a great opportunity off [Matthews]'s shot. We had some chances to get back in it, but obviously we don't want to get to that position in the first place. Starting with myself and the way we started the period, we've got to be better and when we get opportunities, we've got to capitalize."
Tavares gave Toronto a 1-0 lead at 8:24 of the first period, scoring on a one-timer after receiving a backhand pass from behind the net by Marner, who has five assists in his past three games.