Werth hit a game-ending RBI single in the 12th inning and the Philadelphia Phillies won 6-5 in a matchup of NL division leaders.
"I was happy to get the hit and get us out of here," said Werth, who was 3-for-7.
So Taguchi led off the 12th with a single to left for Philadelphia. Chris Coste then sacrificed him to second and Connor Robertson (0-1) intentionally walked Jimmy Rollins to get to Werth, who singled to center.
"I tried to go inside with a cutter, but I left it out over the plate and he got some good wood on it," Robertson said.
Rudy Seanez (4-3) pitched a scoreless 12th to earn the win. He had been battling back spasms in recent days, but felt good enough to pitch.
"I would have been out there for as long as they needed me," Seanez said.
Ryan Howard hit his major league-leading 28th home run for the Phillies, extending his hitting streak to a season-high 14 games with a drive to left-center off Doug Davis in the second inning. He has four homers in his last three games and eight in his last 10.
"I've always known Ryan Howard is a good hitter," Philadelphia manager Charlie Manuel said. "It's good. I'm happy for him."
The West-leading Diamondbacks were extended to extra innings for the second straight game after winning 7-5 in 11 innings at Washington on Thursday.
"We made some mistakes early on, but our bats came alive at the end," manager Bob Melvin said. "They just had one more big hit than we did."
Davis allowed three runs and five hits in six innings. It was his 10th start since returning to the mound following surgery on April 10 to remove a cancerous thyroid.
Kyle Kendrick yielded four runs and nine hits in 6 1/3 innings for the East-leading Phillies.
"We had our share of chances and the bullpen did a good job," Kendrick said. "It was nice to get a win like this."
Arizona's Chad Tracy tied it at 1 with an RBI single in the sixth. He has hit safely in nine of his last 10 games.
Arizona 3B Mark Reynolds was held out of the starting lineup after committing three errors in Thursday's win at Washington. Reynolds has committed a major league-worst 19 errors this season. Reynolds did appear as a pinch hitter in the 11th.