WASHINGTON (AP) - Sometimes there's really no explaining why a pitcher not known for strikeouts suddenly turns into a strikeout artist.
The Washington Nationals had no shortage of theories, however, after Tanner Roark fanned a career-high 15 and allowed only two hits over seven innings Saturday in a 2-0 victory over the Minnesota Twins.
Roark (2-2) twice struck out the side and fanned at least two strikeouts in four other innings. It was only the second time in 52 career starts the right-hander reached double digits in strikeouts - the other was on June 6, 2014, when he fanned 11 at San Diego.
So what happened?
''I was throwing four pitches to lefties and righties,'' Roark said. ''Keeping them guessing, uncomfortable at the plate.''
He sure did.
''On a given day, anybody can be world beater. Today was Tanner's day to do that,'' Nationals pitching coach Mike Maddux said. ''Just to have that special moment.''
And finally, manager Dusty Baker dug deep to come up with this reason: ''He shaved his beard off, so that had something to do with it, probably.''
Roark acknowledged that he never felt so sharp on the mound, and the numbers backed up the assessment.
He threw a career-high 121 pitches, 78 of them strikes. He walked three, got all but six outs via strikeouts and held the Twins hitless over his final five innings. The 15 Ks were five more than he totaled in his first three starts.
Roark began the day with a 27-20 record and 3.15 ERA in 88 games with the Nationals.
Roark and a trio of relievers combined to fan 18, the most by Washington since its arrival from Montreal in 2005.
Blake Treinen and Oliver Perez worked the eighth. Jonathan Papelbon got three outs to complete the combined two-hitter and earn his seventh save.
Ryan Zimmerman drove in two runs and Bryce Harper had a pair of doubles for the Nationals, whose 13-4 start matches the 1981 Expos and 2012 Nats for the best in franchise history.
Phil Hughes (1-3) gave up two runs and six hits in seven innings. Half the hits he allowed came in the first inning, when Washington scored all its runs.
''Phil settled down and did a real nice job of completing his outing,'' Twins manager Paul Molitor said. ''He did everything he could to give us a chance.''
The Twins' lone hits were a first-inning single by Joe Mauer and double by Max Kepler in the second. The defeat dropped the Twins to an AL-worst 5-13.
''Roark had a good day,'' Molitor said. ''He hasn't pitched poorly, but he hasn't pitched great until today. The strikeouts were partly him, partly us. That's a big number, no matter who's out there.''
Washington went up 2-0 in the first when Zimmerman hit a two-run single after Anthony Rendon singled and Harper doubled.
''At the time you're thinking, `It's just two runs, we can hopefully we can find a way to bounce back,''' Hughes said. ''But that wasn't the case today.''
Twins: Leadoff hitter Brian Dozier came in batting .188 with a mediocre .278 OBP. He went 0 for 3 with two strikeouts and a walk.
Nationals: Baker rested leadoff hitter Michael Taylor, who's batting .161 and in a 2-for-18 funk. Asked to explain his decision to use Chris Heisey (.231, 1 RBI) at the top of the order, Baker replied, ''You got any better choices?'' Heisey went 0 for 4.
Twins: RHP Ervin Santana has been scratched from his scheduled start Sunday with a sore lower back, an injury that occurred during batting practice on Friday, assistant GM Rob Antony said. After the game, the Twins recalled RHP Tyler Duffey from Triple-A Rochester to start Sunday and optioned INF Jorge Polanco to Rochester.
Nationals: RHP Joe Ross (blister) still hopes to make his next scheduled start Tuesday. Baker, who watched Ross test the injury Friday, said, ''I don't know if he could throw a full game like that. There's skin over it but it looks kind of like an open wound where they shaved the callus off.''
Twins: Duffey went 5-1 in 10 games as a rookie last year.
Nationals: Stephen Strasburg (3-0, 1.25 ERA) seeks to go 4-0 for the first time. It will be his first career start against the Twins.