CINCINNATI -- Johnny Cueto knows how to prepare for day games, and his routine is working out quite well for him.
Cueto pitched eight crisp innings, Todd Frazier hit a go-ahead homer for the second straight game and the Cincinnati Reds beat the Chicago Cubs 5-3 on Saturday in the opener of a day-night doubleheader.
"Don't get me wrong," Cueto said through an interpreter after improving to 11-0 with a 1.62 ERA in 13 day games this season. "I like throwing at night, but I like pitching in the day, too. It's not really different. It's all in how I get prepared the night before day games."
Xavier Paul and Miguel Cairo added their first home runs of the season as the Reds roughed up another Chicago starting pitcher for three home runs. They hit three off Travis Wood in a 7-3 win on Friday night and three more off Jeff Samardzija.
Cueto (16-6) settled down after allowing Alfonso Soriano's two-run homer in the first. The right-hander gave up three hits and struck out eight, drawing a standing ovation when he walked off the mound for the last time. He also hit David DeJesus, the first batter of the game.
Cueto, who didn't allow a runner past first base after the first inning and retired 19 of the last 20 batters he faced, is the first Cincinnati pitcher since Danny Jackson in 1988 to win 16 of his first 25 starts. He has won seven of his last eight appearances to move into a tie with Tampa Bay's David Price for the major league lead in wins.
"He was dealing," manager Dusty Baker said. "He has to be a serious candidate for the Cy Young Award. We don't talk about it, but that has to be in the back of his mind."
"I've got to keep working," Cueto said. "There's a lot of baseball to go before I can think about that."
Cubs manager Dale Sveum watched Cueto dominate Chicago for the second time in six days. He also pitched eight innings in the Reds' 3-0 win at Wrigley Field last Sunday.
"He did everything," Sveum said. "His off-speed stuff was good. He worked inside."
Aroldis Chapman allowed two hits, a walk and a run -- his first in 24 appearances -- but held on for his 29th save.
The first-place Reds (73-47) began the day with a six-game lead over Pittsburgh and an eight-game advantage over St. Louis in the NL Central.
Frazier also drove in Jay Bruce with a sacrifice fly in the eighth inning. He went 2 for 3 and is batting .600 (15 for 25) with three homers and 11 RBIs in 10 games against the Cubs this season.
"I don't know what it is," said Frazier, a leading contender for NL Rookie of the Year. "It's crazy. I'm comfortable against them and confident, like always. When I'm at the plate, I feel like I can some damage."
Soriano drove a 3-2 pitch 433 feet into the second deck in left field with two outs in the first inning for his 22nd homer. The two RBIs gave Soriano 1,000 for his career.
The Reds responded in the second. Frazier led off with a single up the middle and Paul followed with a 381-foot line drive into the right-field seats on a 2-0 pitch.
Frazier led off the fourth with a drive to the first row of the second deck in left for his 17th homer and third in four games. He also had a two-run shot Friday night that gave the Reds a 4-3 lead.
Cairo added a one-out shot to left on a 1-2 pitch for his first homer since Sept. 21 against Houston, making it 4-2.
Samardzija (8-11) gave up four runs and six hits in five innings. He struck out five, walked none, hit a batter and threw a wild pitch.
The right-hander is 1/3 with a 4.07 ERA in four starts this month.
The Cubs are working on a new contract for SS Starlin Castro, but general manager Theo Epstein said nothing has been finalized yet. ... Both teams recalled pitchers from their Triple-A affiliates to start the second game of the doubleheader. The Cubs promoted LHP Brooks Raley from Iowa, while the Reds recalled RHP Todd Redmond from Louisville for his major league debut. ... Neither team was required to send anybody out to make room. Major League Baseball rules allow teams to add a 26th player to their active roster for doubleheaders such as Saturday's, which was scheduled after a May 1 postponement. ... Soriano joined Barry Bonds, Andre Dawson, Willie Mays, Alex Rodriguez and Gary Sheffield as the only major league players with at least 1,000 RBIs, 400 doubles, 350 home runs and 250 stolen bases in their careers.