WASHINGTON -- Willie Harris couldn't get a sacrifice bunt down to move the winning run into scoring position. Then he failed to execute a hit-and-run.
So when emergency reliever Scott Richmond ran the count full, Harris just wanted to drive the ball somewhere to keep the rally alive.
Nationals manager Manny Acta kept changing the tenor of Harris' at-bat as it unfolded. First he called for a bunt, then tried to get Harris to shoot a ball through the infield with Alberto Gonzalez running on the pitch.
"It's a mouse-and-cat type of game. ... We got all the way to 3-2 and we try to tell [Harris] to be aggressive," Acta said.
Gonzalez led off the 12th with a single against Richmond (5-4). Harris then hit a drive into the Nationals' right-field bullpen for his second home run of the season.
"When I got to 3-2, I was able to get a ball up in the zone and hit it out of the ballpark," said Harris, who made a diving catch in center to take an extra-base hit away from Raul Chavez in the fifth.
The Nationals, with the worst record in the majors, have their longest winning streak since taking seven straight from Aug. 26-Sept. 1, 2008.
"We really feel like we can win every game," Harris said. "When you're losing ballgames, you get a gut feeling you're going to lose a game somehow. Things are going well for us now."
Julian Tavarez (3-4) got the victory with 1 2/3 innings of scoreless relief.
Toronto manager Cito Gaston turned to Richmond, who started and won Wednesday in Philadelphia, because he was down to rookies Dirk Hayhurst and Brad Mills in an overtaxed bullpen.
"We had a lot of guys that weren't available tonight and we got them through the night," Gaston said. "Of course, it would have been nicer to get them through with a win."
Washington's Nick Johnson walked, singled and doubled in his first three times up, extending his streak of reaching base safely to 10 consecutive plate appearances, a Nationals record. That matched the franchise mark set by the Montreal Expos' Rusty Staub in 1969. Johnson's streak ended with an eighth-inning groundout.
But it wasn't enough to prevent a two-game losing streak by the Jays, who scored 23 runs in sweeping three games from the World Series champion Phillies before arriving in D.C.
"[Washington] pitched as well as we have," Gaston said. "They've just managed to outscore us. ... In baseball you don't stay hot all the time."
The Nationals went up 1-0 in the fifth. Harris hit a ground-rule double over the wall in left-center, stole third and scored on Wil Nieves' sacrifice fly.
Brett Cecil, recalled earlier in the day from Triple-A Las Vegas to take the rotation spot of the injured Toronto ace Roy Halladay, allowed eight hits and three runs in seven innings, walking one and striking out four.
Detwiler allowed two runs on six hits over seven-plus innings, walking one and striking out three.
Rolen's fourth-inning single extended his hitting streak to 10 games. ... Washington LHP Scott Olsen, on the 15-day disabled list with left shoulder tendinitis, will make at least one more rehabilitation start for Triple-A Syracuse before he's activated. On Friday, Olsen allowed four runs on seven hits and walked three in 3 2/3 innings. ... Saturday marked the one-year anniversary of Gaston's return as Toronto's manager. In that time, the Blue Jays were 88-69 (.561), the third-best mark in the American League. ... Washington RHP Jesus Colome left the game in the 11th with a right quadriceps strain and is day-to-day.