After reaching the playoffs last season, the Washington Nationals and Baltimore Orioles both seem highly unlikely to get there again.

The Beltway rivals begin a three-game series Monday night in desperation mode, with the Nationals still well behind in the NL East and the Orioles 5 1-2 games back of the AL's second wild card.

Baltimore (73-76) had its already slim chances further reduced with a difficult loss at Tampa Bay Sunday, with the Rays scoring three runs in the last two innings to rally for a 7-6 victory.

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Zach Britton allowed a game-tying homer to Brandon Guyer to begin the bottom of the ninth and later surrendered a triple to Evan Longoria, who scored the deciding run on Kevin Kiermaier's two-out infield hit.

The Orioles fell to 60-2 when leading after eight innings.

''Gloom and doom, we don't do that,'' manager Buck Showalter said. ''We're going to try and win the rest of our games and make it tough on everybody.''

Washington (78-71) may have had its fate sealed by a five-game skid from Sept. 7-12 that included three home losses to the first-place New York Mets. The Nationals have won seven of eight since, however, recording 13 hits to support Stephen Strasburg's 10 strikeouts in Sunday's 13-3 rout of Miami.

''Obviously, (the deficit) is there,'' Yunel Escobar, who had four hits with four RBIs, said through an interpreter. ''But the less we think about it as a team, the better we have a chance of catching up to (the Mets).''

Tyler Moore added a three-run homer and Bryce Harper went 3 for 4 to raise his MLB-leading average to .343.

Harper is 14 for 27 with five homers and 10 RBIs during a seven-game hitting streak. His 41 homers lead the NL, while Baltimore's Chris Davis hit his MLB-leading 43rd in Sunday's loss and is batting .377 with eight homers and 17 RBIs in September.

Davis is just 1 for 12 with five strikeouts against Gio Gonzalez (11-7, 3.83 ERA), who's done his part to keep Washington in the race by going 2-0 with a 1.47 ERA in three starts this month. The last was one of his best, as the left-hander matched a career high with 12 strikeouts over seven innings in Wednesday's 12-2 win at Philadelphia.

Gonzalez held Baltimore to a run in six innings while exiting with a lead in a 3-2 loss at Camden Yards July 10. He lost his previous four starts against the Orioles and is winless in seven since tossing six scoreless innings with Oakland on Aug. 10, 2009.

Matt Wieters is 10 for 17 with a homer against Gonzalez but is hitting .154 with 22 strikeouts in 63 at-bats since Aug. 21.

Harper has never faced Ubaldo Jimenez (11-9, 4.31), who's 5-1 with a 2.61 ERA in seven starts against Washington and 3-0 with a 1.59 ERA in four at Nationals Park. He hasn't opposed them since July 2011 with Colorado, however.

Jimenez yielded four earned runs over 12 2-3 innings in consecutive road wins over Toronto and the New York Yankees before permitting four in five innings without receiving a decision against Boston Tuesday.

Escobar, hitting .431 with 13 runs scored over his last 12 games, is 8 for 21 with a homer against Jimenez.