For Wilson, lack of command was the biggest issue, with the left-hander walking five for the night. But it wasn't the only problem, as he also allowed nine hits.
Angels manager Mike Scioscia and pitching coach Mike Butcher had talked with Wilson about pitching more aggressively in order to get hitters out more quickly and work deeper into games. The lefty had averaged 115 pitches and less than seven innings in his last six starts before Tuesday.
Wilson said their advice didn't include a "to-do list," but with him unable to harness his pitches -- he threw 66 strikes to 48 balls in five laboring innings -- any new plan wouldn't have mattered anyway.
The Halos' defense hurt the starter, too. Third baseman Alberto Collapso missed a grounder off the bat of Derek Norris in the third with the bases loaded, plating two in a four-run inning.
"The one thing I think on C.J. was just his ball-strike ratio, and getting in so many deep counts," Scioscia said. "When all was said and done, maybe if we tighten things up on the defensive side, maybe his linescore's a little better, but the five walks obviously put a lot of guys on base for the A's tonight, and they took advantage of it."
The poor effort added to what's been a trying stretch for Wilson. He's now winless in his last eight starts and has given up 14 runs in his last two outings.
Scioscia said the left-hander's stuff looked "sharp," which is a sign of progress, and that he wasn't off by much with his command.
Even Wilson, though, admitted that he put himself in too many bad positions due to his inability to get ahead of hitters and his lofty pitch count.
"It's just frustrating that we're in a pennant race and I haven't contributed to us winning any games recently," Wilson said.
The starter's short outing meant the Halos' troubled bullpen was forced into early action, and as has been the case this whole 10-game road trip, it didn't answer the bell. The right-handed duo of David Carpenter and Jerome Williams allowed three home runs in two innings, making the team's deficit an insurmountable nine runs.
The A's outburst came after scoring just six runs in their last three games, and they touched up a pitcher in Wilson who shut them out over eight one-hit innings the last time he faced them.
"For whatever reason tonight, we seemed kind of rejuvenated and looked like a team that hasn't been having struggles," A's manager Bob Melvin said. "I thought we looked a little tired the past few days, based on the fact we played so many long and close games. It felt like we were dragging a bit, and boy that was a nice offensive effort, especially against a guy that's been really tough on us in the past."
The Angels looked as hapless on Tuesday as Oakland did on Monday against Jered Weaver, and the lifeless offensive performance came courtesy of a familiar face.
Right-hander Bartolo Colon is a different pitcher now from when he pitched for the Angels from 2004-07, relying more on his ability to change speeds and pure guile to get hitters out. But he's been effective this season, especially lately.
Colon didn't give up a run until there were two outs in the seventh, finally ending his career-high scoreless streak at 22 1/3 innings.
"It's frustrating," Trout said. "Bartolo came out throwing strikes, keeping us off-balance. He was making good pitches and he threw the ball well tonight."
Trout added a solo shot in the eighth, joining Ted Williams (1939), Frank Robinson (1956), Alex Rodriguez (1996) and Jason Heyward (2010) as the only players in history to hit a home run on their 21st birthday.
But Trout's feat, the ending of Colon's streak and the four total runs the team plated were hardly a consolation for the Angels, who looked like a shell of the group that topped Oakland with ease the night before.
Just ask Trout.
"We lost, so it doesn't mean a whole lot," he said of his achievement. "When I look back at the end of the season, that stuff will pop up, but right now it means nothing."