WASHINGTON -- Cubs manager Joe Maddon joked that Albert Almora Jr. has been in the big leagues about "five minutes."

But it took even less time than that for the rookie outfielder to complete his only at-bat of the game Tuesday.

Almora had an RBI double with one out in the ninth inning to break a tie as the Chicago Cubs beat the Washington Nationals 4-3, evening the series between the first-place clubs before a sellout crowd of 41,955.

In his 12th at-bat of the season and MLB career, reserve Almora hit the first pitch from reliever Sammy Solis (1-2) into left-center to score Addison Russell, who led off with a walk and went to second on a sacrifice bunt by David Ross.

"I am just trying to help the team win," said Almora, 22, a Florida native who spent all of last season with Double-A Tennessee. "You try to stay confident. I just tried to stay calm. I just did it for my guys. I am trying to be a team guy."

Almora entered the game to play left field in the eighth. He said he remembered Solis from the Arizona Fall League and nodded to the left-hander as he got into the box.

"This kid is going to play in the big leagues a long time," said Joe Maddon, the Cubs manager. "He jumped on the first pitch. I loved it."

Washington's Anthony Rendon tied the game 3-3 with a sacrifice fly in the eighth off Cubs closer Hector Rondon (1-1), who came back in the ninth to get the last three outs. The Nationals were without closer Jonathan Papelbon, who went on the disabled list earlier in the day.

A sacrifice fly by Washington's Ben Revere in the seventh off reliever Pedro Strop cut the Cubs lead to 3-2. But Strop fanned Jayson Werth for the final out of the inning with a runner on second. Travis Wood got one out in the eighth and before Rondon was summoned for a five-out save.

"He has had plenty of rest," Maddon said of Rondon.

Washington starter Gio Gonzalez yielded five hits, four walks and three runs in 6 1/3 innings before fellow left-hander Oliver Perez came on in the seventh to get two outs. The last win for the erratic Gonzalez came May 2.

"It was a fight. That is the way the game was," said Gonzalez, from the same Miami suburb as Almora. John "Lackey did a great job. I went out there and battled."

Cubs veteran Lackey, making his 400th career start, gave up four hits in six innings with two walks and seven strikeouts. It was the 18th game in a row that Cubs starters had allowed three runs or fewer.

"John was fantastic," Maddon said. "His stuff is really good. He knows what he is doing."

Dexter Fowler had two hits for the Cubs, who have the best record in the majors. Backup catcher Jose Lobaton, who normally catches Gonzalez, had two hits for the Nationals.

The Cubs (44-19) have won five of six this year against Washington (40-25), which fell to 7-9 against the National League Central. The Nationals had won their previous five home games.

"We had opportunities and hit some balls on the nose," said Dusty Baker, the Washington manager. "We played a good game but just came up on the short end."

The Cubs took a 2-0 lead in the third as Jason Heyward had a two-run single. His hit scored Lackey, who had a two-out single and took third on a double by Fowler.

Werth's sacrifice fly in the third pulled Washington to within 2-1.

Ross gave Chicago a 3-1 lead with an RBI single in the fourth.

Lackey won his previous three starts and did not allow a run in his last two appearances, covering 13 2/3 innings. He entered Tuesday with a 2.63 ERA and had not lost since May 11 -- a 1-0 verdict to the San Diego Padres.

Gonzalez entered the game with losses in his last four starts, having allowed 21 earned runs in 22 2/3 innings.

"It was really fun. Our players were into it," Maddon said. "Our guys are really able to process the moment well. I am really proud our youngsters."

And that starts with Almora.

NOTES: The Nationals placed RHP Jonathan Papelbon (right intercostal strain) on the 15-day disabled list Tuesday and activated RHP Matt Belisle from the disabled list. Papelbon is 23-for-27 in save chances since joining the Nationals last July. It is his first time on the DL in his career. "I'm in the best hands I can be in. I think we'll have a good game plan. I'm pretty comfortable that I'll be able to come back stronger," Papelbon said. ... Washington manager Dusty Baker guided the Cubs to a record of 322-326 as the skipper for four seasons from 2003-06, including a trip to the 2003 National League Championship Series against the then-Florida Marlins. ... Nationals bench coach Chris Speier (1985-86) and assistant hitting coach Jacque Jones (2006-07) spent two seasons with the Cubs as players. ... Chicago RHP Jason Hammel (7-2, 2.36 ERA) faces Washington RHP Stephen Strasburg (10-0, 3.03) in the series finale Wednesday. ... The Cubs entered Tuesday with a team ERA of 2.63, the best mark in the National League. The Nationals were third at 3.19. .... Cubs CF Dexter Fowler started and batted leadoff in his 1,000th career game. He singled to right to lead off the game and doubled in the third.