CINCINNATI — Johnny Cueto allowed nothing more than Justin Upton's solo homer in seven innings today, striking out 10 in an overpowering debut while leading the Cincinnati Reds to a 3-2 victory over the Arizona Diamondbacks.

The 22-year-old pitcher threw his 96 mph fastball right by hitters who had never seen it, finishing them off with a hard slider or changeup. Pitching in a steady rain, the right-hander struck out eight of his first 13 batters.

His 10 strikeouts were the most by a Reds pitcher in his big league debut since 1900, according to the Elias Sports Bureau.

The only glaring mistake: Upton led off the sixth with a homer. That was the only hit by a team that batted an NL-low .250 last season.

Arizona's Alex Romero had a sacrifice fly in the eighth, after reliever David Weathers walked the bases loaded. Francisco Cordero pitched the ninth for his first save since the Reds gave him a $46 million, four-year deal to fix their biggest shortcoming.

Jeff Keppinger homered off left-hander Doug Davis (0-1), who failed to make it through the fourth inning of an emotional start. Davis was diagnosed with thyroid cancer last week and is to have surgery on April 10.

In every other way, the gloomy day belonged to a newcomer.

No one expected Cueto to be in this position a year ago, when he started at Class A and got on the fast track. He led all Reds minor leaguers in strikeouts last season, and was one of the most impressive pitchers in spring training.

The question was whether he could control his emotions and his best pitch when the pressure was on. In his next-to-last start of spring training, Cueto walked five of the 10 batters he faced.

Pitching in a light, steady rain that turned the 48-degree afternoon raw, Cueto kept his grip. He set the tone by fanning Chris Young on a 96 mph fastball to open the game.

By contrast, Davis struggled through 3 2-3 innings, which was an accomplishment in itself.

The Diamondbacks were crestfallen when Davis was diagnosed with thyroid cancer in the final week of spring training. The 32-year-old pitcher lobbied hard to make his two planned starts leading up to his operation.

The doctors said it was OK, and manager Bob Melvin gave his approval even though he was amazed by the pitcher's forge-ahead attitude. Davis is expected to miss at least a month while he recovers from the surgery.

Davis needed 29 pitches to get through the first inning, working at his usual, unhurried pace in the steady rain. Brandon Phillips doubled home a run, and Gold Glove second baseman Orlando Hudson let a grounder skitter under his glove for a run-scoring error. Keppinger hit a solo homer in the second for a 3-0 lead.