ST. PETERSBURG, Fla. -- Erasmo Ramirez continues to surprise.

The right-hander turned in his fourth consecutive impressive start, throwing six shutout innings Monday and leading the Tampa Bay Rays to a 6-1 victory over the Washington Nationals at Tropicana Field.

"Nice way to start a four-game series," said Rays manager Kevin Cash, whose team won its fourth straight to take sole possession of first place in the American League East. "I thought Erasmo was really good again, just kept his poise really well out there. ... Lot of good things, a lot of good at-bats."

Ramirez won for the sixth time in his past seven starts, and he has allowed just three runs in his past four starts, spanning 23 1/3 innings.

The comfortable victory was a rarity for the Rays, whose previous eight wins all came by one or two runs.

Tampa Bay (36-29) got a scare in the fifth inning when third baseman Evan Longoria left the game after being hit by a pitch on his left wrist. X-rays were negative, and he is listed as day-to-day with a bruised wrist. Cash said if not for the 6-0 score at the time, Longoria would not have left the game.

"It's just unfortunate that it hit up in the same area," Cash said of Longoria, who was out of the starting lineup for three games last week with a wrist injury. "I wouldn't rule out the possibility of him playing (Tuesday) either. There's nothing seriously wrong there."

Washington starter Gio Gonzalez lasted just 3 1/3 innings for his shortest outing of the season, leaving with a 5-0 deficit.

"It's a tough way to do it today," Gonzalez said. "Obviously, I couldn't put it together, couldn't find the strike zone. You've got a (Tampa Bay) team who's red-hot right now."

After giving up a combined nine runs in his previous four starts, Gonzalez gave up five on eight hits and three walks Monday.

"Gio was just not himself today," Nationals manager Matt Williams said. "Just couldn't throw it where he wanted to throw it. Got behind hitters, lost command of the strike zone. Just didn't have any command at all today."

Rays second baseman Logan Forsythe went 3-for-5 with two RBIs, and rookie right fielder Steven Souza had five walks, tying the team record set by Matt Joyce last year.

The Rays took a shutout into the ninth, then gave up one run before getting a game-ending double play. Tampa Bay left a season-high 13 runners on base, while Washington stranded 12.

Tampa Bay's scoring was sparked by the hustle of center fielder Kevin Kiermaier. In the second inning, he hit what normally would be a routine single to center and never stopped running, beating the throw for a double. He then stole third base and scored on a sacrifice fly by catcher Rene Rivera for a 1-0 lead.

The Rays had three hits and two runs each in the third and fourth innings. Forsythe had an RBI single, and first baseman Jake Elmore hit a sacrifice fly in the third, and then Longoria added a sacrifice fly and Forsythe an RBI single in the fourth.

Kiermaier got a ground ball to carom off the top of first base for a double in the sixth, and he scored on a triple by left fielder Brandon Guyer for a 6-0 lead.

Washington (33-31) was playing just its second series at Tropicana Field as the Nationals, with an 0-3 record coming in. There are only two other places the Nationals have yet to win: They are 0-3 at Oakland and 0-5 at Detroit.

NOTES: The Rays signed OF Grady Sizemore to a minor league deal Monday, and he will report to the team's minor league complex in Port Charlotte, Fla., to begin working out. The 32-year-old hit .245 in 39 games with the Philadelphia Phillies this season. ... C Bobby Wilson, designated for assignment last week by the Rays, cleared waivers and accepted an assignment to Triple-A Durham. ... Nationals RF Bryce Harper got his 200th career RBI on Saturday. Per Elias Bureau, the las