PHOENIX -- If you only watched part of Monday's doubleheader nightcap, chances are you saw a dominant Yu Darvish on the mound carving up the Arizona lineup to the tune of 14 strikeouts.
The Rangers right-hander was masterful for the vast majority of his 116-pitch outing, baffling the first-place D-backs from his fifth offering all the way to his 110th.
The other five pitches, however, ended up costing Darvish and the Rangers dearly.
After allowing two first-inning runs, Darvish served up a game-tying two-run homer in the eighth on Monday night and the Rangers eventually lost on Cliff Pennington's walk-off hit in the ninth, lifting the D-backs to a 5-4 win and sending Texas on its first three-game losing streak of the season.
"That's the game of baseball, you have to play all nine innings," Rangers manager Ron Washington said. "You have to give Arizona credit, they pulled it off. It's unfortunate that a couple pitches made the difference in the ballgame. [Darvish] did everything we asked him to. Unfortunately we just didn't win the game."
The Rangers' two losses on Monday marked the first time the club has been swept in a twin bill since May 3, 2007, against the Yankees.
"They are all tough to swallow," said Rangers catcher A.J. Pierzynski, who collected a pair of hits and drove in two in the nightcap. "We had a chance to win both of those games. Just wasn't meant to be."
Equipped with a two-run lead in the eighth, Darvish allowed a leadoff single to pinch-hitter Wil Nieves before Didi Gregorius took a 2-0 cutter over the middle of the plate and deposited it over the right-field fence to tie the game.
"I had to get a strike in there, I didn't want a 3-0 count," Darvish said. "I just tried to hit the corner but I missed and he hit well."
The two runs marked the first time the Rangers' ace has yielded a run after the sixth inning this season. Even though the homer came on Darvish's 111th pitch of the game, Washington had no regrets afterward about not going to the bullpen sooner.
"He was throwing the ball well, why would I get him out?" Washington said. "He went from the second to the eighth inning just dominating. He was fine. You have to give Gregorius credit. I'm not second-guessing anything I did tonight."
After the Rangers went down quietly in their half of the ninth, Miguel Montero smacked a leadoff double to right field off Jason Frasor in the bottom of the frame. The right-hander then struck out A.J. Pollock before Robbie Ross came in and served up the game-winning hit down the right-field line two batters later.
"He's been really good, obviously, all year," said Pennington of Ross, who has a 0.39 ERA in 2013. "I knew he had a really good cutter, mid-90s fastball and so I just tried to make sure I didn't try and pull it because you can't pull that cutter. So I was just trying to stay inside it and got it to go through. It was huge."
Back in the first inning Monday night, Darvish abruptly found himself down by a pair of runs before he even broke a sweat.
On back-to-back fastballs, the right-hander served up a single and a triple to Gerardo Parra and Gregorius, the first two batters he faced. Two pitches later, a sacrifice fly off the bat of Eric Chavez put the Rangers in an early 2-0 hole.
Following the rough start though, Darvish was lights-out over the next six innings, allowing just one runner to reach scoring position while fanning more than half of the D-backs that stepped to the plate.
"After the first two hitters you could tell they were going to be super aggressive, so we started throwing more breaking balls to even the playing field," Pierzynski said. "They had no chance. He pitched really well."
Once the Rangers battled back and grabbed their first lead of the game in the sixth, 4-2, Darvish appeared well on his way to securing his eighth win of the season.
Then came the eighth inning and Gregorius' backbreaking homer.
"He just made one bad pitch," Pierzynski said. "It didn't cost us the game, but it gave them life."
The righty retired one more batter before Washington went to the bullpen. In his 7 2/3 innings of work, Darvish allowed four runs on seven hits, and the 14 strikeouts tied a career high for the third time this season. He also accomplished the feat on April 2 vs. the Astros and May 5 against the Red Sox.
The last pitcher to record at least three games of at least 14 strikeouts in a season was Randy Johnson in 2004.
"I don't really care about that, baseball isn't a competition of getting strikeouts, it's about winning," Darvish said. "No matter how good you pitch, if you don't win the game, it doesn't really matter."
The Rangers came into Monday's doubleheader following a 13-inning affair in Seattle on Sunday, and after playing three games in two days in two cities, the club will head home for another two games with the D-backs beginning Wednesday in Arlington.
"We're looking forward to the day off but being fatigued and traveling didn't come into play," Washington said. "We went in here and got beat two games. Arizona won it."
Tyler Emerick is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.