Ubaldo Jimenez's outing Tuesday night wasn't always pretty.

It was, however, memorable.

Jimenez pitched six gritty innings to earn his 100th career win and added an RBI single as the Baltimore Orioles beat the Washington Nationals 4-1 in the rain-delayed opener of a series between teams fighting to remain in the playoff race.

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The 31-year-old Jimenez (12-9) won his third straight decision for Baltimore, which began the night trailing three teams and six games back for the AL's second wild card.

"It seems like yesterday that I got to the big leagues and I already have eight years and 100 wins, so it's been a really enjoyable moment," Jimenez said.

The Nationals remained 6 1-2 games back of the Mets, who lost to Atlanta, in the NL East. But New York's magic number to clinch the division dropped to six.

Jimenez walked five, but allowed just an unearned run on three hits while also striking out five.

"I've said it a hundred times, deception is part of his ability to get people out with the fastball and the movement, and that's how he creates it," Orioles manager Buck Showalter said when asked about the walks.

"You're going to have to sometimes live with it," Showalter said. That's a little bit more than you want to."

Jimenez is having a bounce-back season. He's doubled his win total from 2014, a year in which he spent time on the disabled list and finished 6-9.

"In baseball you have to forget quick, because this is a game that can really eat you alive if you think too much," he said.

Monday's opener was postponed by rain. The teams are scheduled to play a makeup game Thursday.

Darren O'Day pitched the ninth inning for his fourth save.

Chris Davis and Steve Pearce had RBI doubles for Baltimore.

Bryce Harper set the Nationals record for walks, getting three free passes that upped his season total to 118.

Michael Taylor had two hits for Washington, which had won seven of eight.

"Three hits, a lot of flyballs," manager Matt Williams said after Washington hitters stranded nine baserunners. "We've been coming through a lot lately, but not tonight."

Gio Gonzalez (11-8) lasted 4 2-3 innings, allowing four runs on six hits and two walks.

He came in having allowed just three earned runs over his last three starts.

Gonzalez walked two batters with one out in the second inning and both scored.

With runners on first and third, Jimenez lined a two-out single to center to make it 1-0. J.J. Hardy scored on a Nolan Reimold single.

The Orioles have committed the fewest errors in the majors, but they picked up two in the fourth.

Junior Lake, filling in for Adam Jones in center, dropped a flyball for a two-base error to start the inning.

Another error, this one by Jonathan Schoop, allowed Washington to score, but the Orioles then turned a sparkling 2-5-4 double play (aided by a replay review) with Schoop covering first to end the threat.

The Orioles bumped it to 4-1 in the fifth.

TRAINER'S ROOM

Orioles: Showalter was unsure if Jones (back spasms) would return Wednesday. . RHP Miguel Gonzalez (right shoulder tendinitis) will pitch a simulated game Wednesday.

Nationals: An MRI revealed INF Danny Espinosa has a small tear in his right hamstring, Williams said. "We'll have to be cautious with him for sure," said Williams, who didn't have a timetable regarding Espinosa's availability. ... RHP Jordan Zimmermann could have been moved ahead of RHP Tanner Roark to pitch Thursday's makeup game with Baltimore on normal rest, but has a stiff neck and will pitch Friday as planned.

UP NEXT

Baltimore RHP Chris Tillman (9-11, 5.19) looks for his first win since Aug. 17 when he opposes Max Scherzer (12-11, 2.90). Scherzer has allowed just two runs over 15 innings in his last two starts.

CHASING JUAN

Jimenez became the 11th pitcher Dominican-born pitcher to earn 100 career wins. Hall of Famer Juan Marichal leads the way with 243 wins, and current Orioles pitching coach Ramon Martinez has 135.

"I was able to watch Ramon and Pedro Martinez every five days on the TV when I was a little kid in the Dominican," Jimenez said. "I never dreamed I was going to be in the same league."

FISTER FORGES ON

Former Washington starter Doug Fister threw two scoreless innings in relief, striking out four. In his last five appearances, Fister is 1-0 with a 0.00 ERA in 9 1-3 innings.