CHICAGO (AP) — The Washington Nationals' two biggest stars were full of praise for each other Wednesday night. After what they did against the Chicago Cubs, it was merited.

Bryce Harper hit his 18th home run, Max Scherzer struck out a season-high 13 to outduel Jon Lester and Washington beat Chicago 3-0.

The top two free-agent pitchers on the market last offseason, Scherzer (6-3) and Lester faced off in a memorable matchup in the finale of the three-game series. Scherzer, who signed a seven-year deal worth $210 million with Washington, was better than his counterpart, throwing seven scoreless innings while allowing five hits and one walk to win his fifth straight start.

"He's unbelievable," Harper said. "He's definitely as good as advertised."

Scherzer and three relievers combined to shut out the Cubs and take two of three from Chicago. Drew Storen pitched a scoreless ninth for his 16th save in 17 attempts.

In support of Scherzer, Harper continued his torrid May and pulled even with Seattle's Nelson Cruz for the major-league lead in homers. Harper's sixth-inning home run off Lester (4-3) was a line drive into the left-field bleachers, giving him 13 this month and 28 runs batted in during May.

"I've said, as well as he's doing right now, I still feel like he can get better, and that's the crazy thing," Scherzer said.

Matt Grace started the eighth for Washington and allowed a Jorge Soler double and hit Anthony Rizzo before being replaced by Casey Janssen. Janssen got Kris Bryant to pop out before Dexter Fowler's sacrifice advanced the runners to second and third. Starlin Castro then grounded to short to end the threat for the Cubs.

"We did not play our best game and we still had a chance to win that game," Cubs manager Joe Maddon said.

Danny Espinosa added a solo home run in the ninth off Travis Wood, and Ian Desmond extended his hitting streak to 12 games with a one-out double in the first.

Beyond Harper's home run and an unearned run in the fourth, Lester kept pace with Scherzer. The veteran left-hander, who joined the Cubs after signing a six-year, $155 million contract, went seven innings and allowed two runs (one earned) and seven hits while matching a season-high with 10 strikeouts.

"Obviously, Max threw the ball a little better than I did," Lester said.

Lester did make some history, but it was with his bat and not the way he'd want. He went 0 for 2 and dropped to 0 for 59 lifetime to move him into sole possession for the longest hitless streak to begin a career, moving past Joey Hamilton (0 for 57) to set the new mark.

The Cubs lost their fourth in six games, as Washington's big-money ace was slightly better than Chicago's.

"He's got extra gears that a lot of people don't have," Nationals manager Matt Williams said. "We saw that tonight."

CASEY ON THE MOUND

Janssen's one inning of work drew kind words from his teammates and manager after Wednesday's win. "It was awesome. To me, he showed us how much he competes on the mound tonight," Scherzer said. "How much he wants the ball, and the type of marbles he has, for lack of a better term."

TRAINER'S ROOM

Nationals: RHP Doug Fister (right forearm tightness) began the first day of a throwing program by playing catch Wednesday. Fister was placed on the disabled list May 15. . IF Anthony Rendon (strained oblique) played five innings in a simulated game in what manager Matt Williams referred to as a positive sign.

Cubs: Soler didn't start, but manager Joe Maddon said that was to give him an extra day off before Friday's series opener with Kansas City.

UP NEXT

Nationals: RHP Stephen Strasburg (3-5, 6.50) faces Reds RHP Anthony DeSclafani (2-4, 3.46) on Friday in Cincinnati.

Cubs: RHP Jake Arrieta (4-4, 2.95) faces Kansas City RHP Edinson Volquez (4-3, 2.77) at Wrigley Field.