"If I get that pitch down, it's an out," Duke said. "I didn't execute."
"That was a big blow," added manager John Russell. "He needs to make a better pitch."
Duke had allowed two singles -- including one to opposing starter Carlos Monasterios -- to precede Ethier's seventh home run of the season.
Duke went on to finished six innings and limited the Dodgers to just one additional run. He showed improved command from his last two starts, though the outing still wasn't as clean as his first three starts of the year.
After allowing just five earned runs in his first three starts of the season (all Pittsburgh victories), Duke has since allowed 18 earned runs in his last 15 innings. He's lost all three of those games.
"He's better than that," Russell said of Duke's overall effort on Saturday. "He made a few mistakes tonight, and he's better than that."
Saturday's outcome may have hinged around the pitch Duke threw, but it was a couple of others that were at the center of much of the talk afterward. Andrew McCutchen was brushed back and knocked down by consecutive fastballs from Dodgers reliever Ramon Ortiz in the fifth.
McCutchen, who had given the Pirates the early lead with a first-inning homer, saw an 0-1 pitch come high and tight at his chest. The next pitch went at McCutchen's head. He fell down to avoid being hit.
McCutchen was asked afterward if he felt the pitches were thrown at him intentionally, possibly in retaliation for his earlier home run.
"I just look at it as a couple pitches got away from him," McCutchen said. "That's all. It happens. Not every pitch is going to be right down the middle. Shake it off and get ready for the next pitch."
Though McCutchen did not make a big deal about it, others in the Pirates' clubhouse weren't as politically correct. And they voiced obvious displeasure.
"To have two pitches sail by his head, something's going on," outfielder Ryan Church said. "Bush league. If you're going to throw at someone, don't throw at their head."
"I don't like it," added Russell.
Ortiz, who picked up his first win since 2007 with three scoreless innings of relief, said his only intention with the pitch was to throw inside.
"Let me tell you something: Everybody, not only me, everybody has to pitch inside," Ortiz said. "If you don't pitch inside, you're done. You have to move the feet. To everybody."
Two innings later, the Dodgers took exception to reliever Jack Taschner's first pitch, a fastball thrown behind Ethier. That started a spat between Dodgers catcher Russell Martin, who was standing on the top step of the dugout, and Taschner.
"Obviously there were a couple of pitches up and in at McCutchen," Martin said. "Obviously, they didn't like it. You don't want to hit anyone in the head. That's the way you're supposed to get the guy out, pitch him up and in. Then he threw the ball behind Andre."
The Pirates' offense was much quieter than all this, finishing with just five hits in all. After scoring 13 runs in their final two games in Milwaukee, the Pirates have now scored just five in the first three games of this series.
They had some chances to get Monasterios, a Rule 5 Draft pick making his first Major League start, on the ropes early, but couldn't capitalize. In fact, McCutchen's solo shot in the first could very well have been a three-run blast if not for the two-hitter sequence before him.
Aki Iwamura drew a walk to start the game but was soon thrown out trying to steal. Andy LaRoche then thought he drew a walk on a low and outside, 3-1 pitch from Monasterios. Home plate umpire Doug Eddings saw it differently, called it a strike, and LaRoche popped out on the next pitch.
LaRoche came up with the bases loaded an inning later and grounded out to end the inning and the threat. Another opportunity missed.
"We've got to do better offensively," Russell said. "We're going to have to start doing something to take the heat off our pitchers."
Monasterios was effectively erratic as he finished two more innings, and the Dodgers' bullpen never let the Pirates scratch their way back in.
"I didn't think he did anything special," Lastings Milledge said of Monasterios. "I didn't think he was Cy Young or anything. But he got the job done."
The loss dropped the Pirates to 3-6 on this road trip, which ends with Sunday's series finale.