"Bad execution. Left the pitch in the middle, and I paid for it," Watson said.
"He missed his location. Wanted to go up and in, and it came back over the middle part of the plate," manager Clint Hurdle said.
Here is the point, however: Frazier just showed what big league hitters do to mistakes; and they relatively rarely get to do it, because the Watsons keep them from doing it.
"I didn't execute the pitch. It wasn't where I wanted it to be," Watson said. "Just have to get back on the horse Wednesday. There are 161 more of these. We'll put it behind us and show up and get a W."
For Frazier to hit a three-run homer, there obviously had to be two men already on base: Billy Hamilton had dribbled a single up the middle, then Joey Votto went opposite-field for another single. Add Frazier, and that's three men reaching base against Watson --- one fewer than in all of Spring Training, when in eight scoreless appearances he gave up only three hits and one walk while striking out 11.
Hurdle shrugged off the two men on base for Frazier's winner.
"A ground ball through the middle of the infield [on Hamilton's single]. And we thought we struck out Votto," said Hurdle, alluding to a two-strike checked swing that got the safe sign from third-base umpire James Hoye.
"Did I think I had Votto? You're asking the wrong guy," Watson said. "I have the wrong angle. The umpire said, 'No,' so you move on -- and he got me on the next pitch.
"It's tough, definitely. Opening Day, we got out of the chute good, fought back on the huge [Andrew McCutchen] homer. Then I give up three to put us down, with [Reds closer Aroldis] Chapman coming behind me."
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. Follow him on Twitter @Tom_Singer. This story was not subject to the approval of Major League Baseball or its clubs.