"Whoever said solo home runs don't beat you is a liar," Phelps said.
The home run, projected by Statcast™ to have traveled 378 feet with an exit velocity of 101 mph, came on a full-count, 84.7 mph changeup. The Marlins didn't have a problem with the pitch selection. It came down to the execution of the changeup.
"I'm telling myself not to walk him right there," Phelps said. "It just happens when you tell yourself that, and you throw it down the middle of the plate."
Crawford was the thorn in the Marlins' side all series. On Monday night, the San Francisco shortstop had seven hits -- including the decisive RBI in an 8-7 win in 14 innings.
On Wednesday, he had two hits, with his homer to lead off the fourth inning providing all the support Jeff Samardzija and four relievers needed.
"The selection was good, just didn't get [the changeup] down," Marlins manager Don Mattingly said. "Some guys, 3-2 changeup, you've got to tip your cap a little bit."
Home run aside, Phelps had an effective second start since moving from the bullpen to the rotation. He threw five innings, allowing the lone run, with three walks and five strikeouts.
"[Crawford] is an All-Star-caliber player," Phelps said. "He's got that flat swing. He stays in the zone a long time. I wasn't really commanding my fastball in there. If I was, it was probably where I would have gone at 3-2. I got a swing and miss early in the count with my changeup. I had a good feeling because it was feeling pretty good today. I got a handful of swings and misses on it."
Phelps' afternoon ended after five innings due to a rising pitch count that reached 91.
"It was one of those games," Mattingly said. "David, obviously, he threw the ball well. The one pitch to Crawford, the changeup, ends up being the deciding factor."
Phelps has given up five home runs in 63 2/3 innings.
"I'm happy I gave my team a chance, but I'm not in it to lose games," the right-hander said. "The last two months, I want to go out and get every [win] we can get."
Joe Frisaro has covered the Marlins for MLB.com since 2002. He writes a blog, called The Fish Pond. Follow him on Twitter @JoeFrisaro and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.