ST. LOUIS -- Luis Castillo knew his start on Sunday against the Cardinals would be an uphill battle from the start.
"At the beginning of the first inning, I knew my command wasn't good enough," Castillo said through an interpreter. "When that happens, you've got go out there and compete, and that's what I did for the rest of the game and I was able to pitch into the fifth."
Castillo's control issues, the Reds' quiet offense and reliever Kevin Quackenbush's rough outing added up to a 9-2 loss that completed a three-game sweep for the Cardinals at Busch Stadium.
Castillo (1-3) gave up three runs on seven hits and a season-high four walks in five innings, as the Reds lost to the Cardinals for the seventh straight time this season and 11th time in a row dating back to Sept. 14, 2017, matching St. Louis' 11-game streak against Cincinnati in 1949.
The Reds fell to 3-18, the worst start through 21 games in franchise history.
Castillo pitched out of trouble in the first, fourth and fifth innings to limit the damage, but he created some extra trouble for himself by his inability to cleanly field a William Fowler bouncer that was ruled an infield hit and scored the Cardinals' second run in the third.
"In that situation, sometimes you rush," Castillo said. "That's what I did trying to get the out at home plate."
Reds interim manager Jim Riggleman chose to look at the positives regarding Castillo.
"It shows how talented he is to only give up three runs because he was not sharp at all," Riggleman said. "But there's better days for him and for the ballclub, and we're always happy to hand him the ball and run him out there because we know how talented he is."
Castillo's velocity was in the mid-90s on Sunday, not nearing triple digits as it did last year. But Castillo said it's there if he needs it.
"I'm not sure where his velocity was last year for most of the year," Riggleman said. "He might have been a tick higher than he is right now. But everything will be looked at. He looks dominating at times and gets the necessary groundball double play and all that, but for his talent, his repertoire of pitches, it should not be this big a struggle at this time."
The Reds' bullpen, which had gone 19 consecutive scoreless innings before a Yadier Molina home run in the seventh of Saturday's loss, surrendered six runs in three frames on Sunday. All of those runs were charged to Quackenbush, who allowed a three-run homer to Paul DeJong in the seventh and a two-run double to Greg Garcia in the eighth to break open a one-run game.
Cincinnati couldn't muster much against Cardinals starter Miles Mikolas (3-0), who permitted two runs (one earned) and struck out a season-high six batters over seven innings. The Reds capitalized on a Matt Carpenter throwing error to allow Jose Peraza to reach to lead off the sixth. Jesse Winker and Joey Votto followed with RBI hits for the Reds' two runs.
"I can promise you this: Hitters -- whether the results show or not -- they're giving you 100 percent when they step into the batter's box," Riggleman said. "That's where they make their money. Their focus is going to be there. It's just not happening right now the way we've seen it the last couple of years with pretty much the same group."
MOMENTS THAT MATTERED
A pair of inning-ending double plays thwarted potential Cardinals scoring chances and kept the Reds close. In the first, Castillo escaped a bases-loaded, one-out jam by getting DeJong to ground into a 5-4-3 double play.
In the fifth, third baseman Alex Blandino snared a liner off of the bat of Tyler O'Neill and doubled off Fowler at third with an unassisted double play.
"The first one was huge because we're going to have to get someone up in the bullpen in the first inning there," Riggleman said. "And the last one was a line-drive bullet. That's not a groundball double play that you're feeling like [it's a] great pitch. The guy squared it up pretty good, so we were fortunate there."
Votto's RBI single in the sixth moved him past Justin Morneau for the second-most hits all time for a Canadian-born player. Votto's 1,604 career hits trail just Larry Walker (2,160).
HE SAID IT
"Messages are so weak. You either got it or you don't. You either can do it or you can't. Messages are the biggest waste of time. You're either capable or you're not." -- Votto, on the Reds' offensive struggles
Right-hander Sal Romano (0-2, 5.75 ERA) seeks his first win of the season as the Reds open a four-game home series against the Braves, who counter with righty Brandon McCarthy (3-0, 2.91 ERA), on Monday. Romano won his lone career start against the Braves, allowing just one run in seven innings on Aug. 18, 2017. First pitch is scheduled for 6:40 p.m. ET.