CINCINNATI (AP) -- Pedro Alvarez singled home a pair of runs in the first inning, and the Pittsburgh Pirates ended Mat Latos' streak of 21 regular-season starts without a loss, beating the Cincinnati Reds 4-0 on Tuesday night.
Latos (6-1) hadn't lost a regular-season game since last August, setting a club-record streak of avoiding defeat. He couldn't overcome Pittsburgh's three-run first inning.
Charlie Morton (1-1) was better during his second start since returning from elbow surgery. He gave up three singles and threw 61 pitches in 5 1-3 innings, starting the Pirates toward their NL-leading 12th shutout.
Latos had nine of Cincinnati's 17 strikeouts, which matched the club's nine-inning record. The Reds also had 17 strikeouts on opening day, but that came in a 13-inning loss against the Los Angeles Angels.
Cincinnati's lineup managed four hits while getting shut out for the second time in their last four games.
The Ohio River rivals have split the first two games of their four-game series, leaving the Reds a half-game ahead of the Pirates. They've been right behind the NL Central-leading Cardinals most of the season.
There was an undercurrent from Monday's game, when Reds closer Aroldis Chapman threw an up-and-in fastball that leveled Neil Walker. The Pirates weren't happy about the pitch's location.
Morton's first pitch plunked Shin-Soo Choo on the leg. Morton also threw one inside to Joey Votto, who refused to budge from the box. Votto flied out, and that was the end of the drama.
The focus shifted back to Latos' long winning streak.
The right-hander hadn't lost since Aug. 24, when the Cardinals beat the Reds 8-5. In the last 21 starts, he'd gone 10-0 with a 2.80 ERA. The Reds were 17-4 during that streak. Also, Latos had never lost to the Pirates, going 4-0 in eight starts with a 2.29 ERA.
Finally, they caught him in a slow start.
He struggled with his control at the outset, needing 32 pitches to get through a 19-minute first inning. Starling Marte tripled and scored on Russell Martin's infield single, giving Pittsburgh a run after only four pitches. Latos walked Garrett Jones and Walker, and Alvarez singled for two more runs.
Latos settled down after the first, fanning eight of the next 11 batters. The problem was his pitch count, which was at 88 when he left for a pinch hitter with two runners aboard in the fifth inning. His streak was left in the hands of the bullpen and the offense.
They couldn't bail him out. Marte singled home another run in the seventh.
Morton had a lot to do with it, too.
The right-hander dominated the Reds in 2011, giving up only one run in two complete games at Great American Ball Park. He had his right elbow rebuilt last June 14 and returned to the majors last Thursday, allowing four runs and seven hits in five innings of a 10-0 loss to San Francisco.
He was much better this time, an encouraging sign for a Pirates rotation hit hard by injuries. Tony Watson, Mark Melancon and Jason Grilli finished it.
NOTES: The Pirates agreed to terms on Tuesday with C Reese McGuire, their first-round pick and the 14th overall selection in this month's draft. ... Pirates LHP Wandy Rodriguez, on the 15-day DL retroactive to June 6 with a tight left forearm, will throw all of his pitches in a bullpen session on Thursday. If he comes out of that without problem, he will make a rehab start in the minors on Sunday. ... Choo has been hit a career-high 19 times, most in the majors.