Matt Harvey explains how it felt to get back on the mound in his debut with the Reds on Friday night. (1:20)

LOS ANGELES -- Matt Harvey fired a second-inning fastball that felt noticeably good coming out of his hand -- better than any pitch had felt in a long time. He peeked at the right-field scoreboard to check whether the radar gun validated his inclination.

It read 96 mph.

"I hadn't seen that in a while," Harvey said. "It was good to know it's still in there."

Harvey breezed through four scoreless innings in his Cincinnati Reds debut on Friday night, giving up only one hit -- on a fly ball that should have been caught -- and striking out two batters in a matchup against the struggling Los Angeles Dodgers, setting the tone in an eventual 6-2 victory at Dodger Stadium.

Harvey, on a limited pitch count for what represented his first start in more than three weeks, required only 55 pitches to record 12 outs. Thirty-two of them were strikes and two of them reached a season-high velocity of 95.8 mph.

"It's a good first start," Harvey said, his 2018 ERA dropping from 7.00 to 6.10. "Obviously it's only four innings; there's a lot of work and a lot of season left. But I think to go out there and be successful and get outs, help a team win, is very important."

Harvey, acquired from the New York Mets only three days earlier, took the mound after a 34-pitch, 21-minute top of the first inning. The 29-year-old right-hander felt what he called "first-time jitters," and it showed when his first three fastballs veered off the plate. But Harvey came back to retire Chase Utley on a flyout, then made quick work of the next three hitters.

With one out in the second, Cody Bellinger hit a towering fly ball that resulted in a triple after right fielder Scott Schebler lost sight of it. Harvey brushed it aside, struck out Chris Taylor on a high slider, then got Max Muncy to line out to center field.

The next six batters were retired in short order.

"He threw the ball well," said Reds interim manager Jim Riggleman, who will start Harvey again on the road against the San Francisco Giants on Wednesday. "All of his pitches were working."

Harvey, once hailed as "The Dark Knight," was arguably the game's greatest pitcher for a brief moment in time. He started the All-Star Game and finished fourth in National League Cy Young Award voting during his first full major league season in 2013. Tommy John surgery followed shortly thereafter, but Harvey was once again dominant throughout 2015, a World Series-bound season that saw him rack up significantly more innings than he and his agent, Scott Boras, anticipated.

Harvey hasn't been the same since.

His 2016 season began with diminished velocity and ended with surgery to repair thoracic outlet syndrome, a procedure that has proven exceedingly difficult for pitchers from which to recover. His 2017 season included a stress fracture in his shoulder and was bookended by struggle. In 2018, he was demoted to the bullpen, then designated for assignment after refusing a trip to the minor leagues, then dealt to the last-place Reds in exchange for a catcher, Devin Mesoraco, and some cash.

Harvey posted a 2.53 ERA in 427 innings from 2012 to 2015 but collected a 5.93 ERA in 212 1/3 innings with the Mets over these past three years, his velocity dropping from 97 mph to about 93. He gave up 21 runs, 33 hits and nine walks in his first 27 innings of 2018, but he spoke optimistically upon meeting his new Reds teammates on Thursday afternoon.

"It's in there," Harvey said then. "It just needs to come out. I just need to relax and let it happen."

Reds catcher Tucker Barnhart didn't have much time to prepare for Harvey's debut, but he made the most of it. He came in at about 1 p.m. PT, watched video of Harvey's starts from 2013 and 2015, looked closely at his usage patterns, then cross-referenced it with what he did over these past three seasons.

"It helped out," Barnhart said. "I felt we were able to use a good four-pitch mix tonight. That was something that I had seen in the video that lacked a little bit [in recent years], whether it was based on circumstance or something that he was trying to do. It didn't sound like he was aiming to do that; it just seemed like it was circumstantial."

Harvey threw 31 fastballs Friday. But Riggleman was impressed with the sharpness of his slider and changeup, and Harvey also flipped a handful of curveballs in for good measure. He generated only two swinging strikes and recorded nine of his outs through the air, a trend that will not play favorably at the Reds' unforgiving home stadium.

But Harvey experienced real, legitimate success Friday night, and that in itself is valuable.

"I didn't really know what to expect," Riggleman said. "I was just really happy for him."

"It's a competitive game, so no matter what, you're always going to try to get better and better each time," Harvey said when asked if four innings was enough to validate his belief that he could continue to be an effective starting pitcher. "Tonight was a good first start, and we just have to keep working from here."