The Blue Jays scored three runs against Brad Brach in the bottom of the ninth to tie the game at 4.
In the bottom of the 10th, Teoscar Hernandez hustled a leadoff double against Miguel Castro (1-2). Justin Smoak was walked intentionally. Kendrys Morales and Luke Maile struck out before Diaz lined his game-winning hit to left.
Danny Barnes (2-1) pitched a perfect top of the 10th with two strikeouts to pick up the win.
Austin Wynns hit his first career major league home run, and Danny Valencia and Mark Trumbo also hit solo shots for Baltimore.
Curtis Granderson homered for Toronto.
Maile took a one-out walk from Brach in the ninth and advanced to third on a double by Diaz. Randal Grichuk hit a two-run double, cutting the deficit to 4-3.
Pinch hitter Devon Travis walked, and Kevin Pillar tied the game with an RBI single. Castro replaced Brach and ended the inning on a double-play grounder by Yangervis Solarte.
Baltimore starter David Hess allowed one run, five hits and two walks with four strikeouts in six-plus innings.
Toronto starter Jaime Garcia gave up one run, four hits and three walks (one intentional) over six innings. The left-hander struck out six.
The Orioles led 1-0 in the first inning after Trey Mancini led off with a double, took third on a groundout and came home on Manny Machado's sacrifice fly.
Granderson tied the game when he led off the bottom of the first with his fifth homer of the season. It was his 46th career leadoff home run.
Tyler Clippard took over from Garcia in the seventh and surrendered the home run by Wynns with one out to give the Orioles a 2-1 lead. Clippard struck out the other three batters in his lone inning.
Hess was replaced by Mychal Givens after Morales led off with bottom of the seventh with a single. With two outs, Grichuk beat out an infield single but Gio Urshela fouled out to first.
John Axford gave up Valencia's sixth homer of the season and Trumbo's third with one out in the eighth.
Baltimore's Richard Bleier pitched around a single in the eighth.
--Field Level Media
Baltimore | Toronto | |
David Hess | Player | Jaime Garcia |
No Decision | W/L | No Decision |
6.0 | IP | 6.0 |
4 | Strikeouts | 6 |
5 | Hits | 4 |
1.50 | ERA | 1.50 |
Baltimore | Toronto | |
Mark Trumbo | Player | Randal Grichuk |
2 | Hits | 3 |
1 | RBI | 2 |
1 | HR | 0 |
5 | TB | 5 |
.500 | Avg | .750 |