Cliff Lee dashes to and from the mound, and when he picks up a baseball, he usually will throw a fastball or a cutter. He does not rely on video or scouting reports, usually just those pitches. They make him one of the game's best pitchers and they are simple. That is why it was so hard for him to justify thinking any other way.

"I've been told that my whole career - to throw more curveballs," Lee said.

The curveball was not the singular reason for Lee's absurd June or the Phillies' 5-0 victory over Boston on Tuesday night at Citizens Bank Park. It is not the pitch he used to record the majority of his 126 outs this month. It's not his best pitch. It's not even his third best.

"But," Lee said, "I think I'm wising up that I need to throw it more, no matter what."

The results are in resounding favor of more curveballs. Lee fired his third consecutive shutout Tuesday, joining Hall of Famer Robin Roberts as the only two Phillies pitchers to ever do so. He has not allowed a run in 32 straight innings, the longest streak of his career. It's the longest scoreless streak for a Phillies starter since Roberts twirled 322/3 scoreless innings 61 years ago.

In June, Lee threw 42 of a possible 45 innings in five starts. He allowed one run on 21 hits, with eight walks and 29 strikeouts. That yields a crazy 0.21 ERA for the month.

"He has control and command of the game," manager Charlie Manuel said.

At the end of May, Lee's ERA was nearing 4.00. In June, he located his fastball and cutter better. He avoided predictability in his first pitches. And he threw more curveballs than ever before.

In his first 12 starts, Lee threw his curve 7.6 percent of the time, according to Pitch F/X data. In five June starts, curveballs accounted for 11.7 percent of his pitches. It has been his third-most used pitch, eclipsing the change-up. Pitching coach Rich Dubee suggested that Lee add the curveball more often. The reasoning lies in common sense.

"It's the biggest separation between my fastball," Lee said. "With as many fastballs and cutters as I throw, it messes with their timing more than my change-up. It's a big pitch for me."

With Lee's dominance, this was a perfect night for the Phillies. Their ballpark was sold out for the 167th straight time for a game against a franchise whose fans used to pack the stands and overrun the locals. The inconsistent and maligned offense scored five runs off Josh Beckett, who had allowed four runs in all of May and five total runs in three previous June starts. Beckett began the day with the best ERA in the majors (1.86).

Both Domonic Brown and Shane Victorino belted two-run home runs, and that was plenty. The Phillies are now 34-3 (.919) when scoring four or more runs, by far the best winning percentage in baseball.

Otherworldly pitching will guarantee success with a pinch of hitting. Lee lowered his ERA to 2.66, incredible considering that he entered the month steadily creeping toward an ERA of 4.00. He held Boston, the majors' best offense, to no hits through the first five innings.

At times, Lee simply toyed with the Boston hitters. He dropped a curveball with a 1-2 count on Mike Cameron in the eighth and the rightfielder was helpless, his bat frozen. Lee, amused by what had happened, smiled and pounded his left fist into his glove.

When Lee has conviction in all four of his pitches, hitters have no idea what's coming. Catcher Carlos Ruiz has a powerful arsenal at his disposal.

"It makes it a little easier for me to call the game," Ruiz said.

He laughed. On this night, Ruiz could put down any sign and Lee would deliver. And just maybe, a spectacular June finally convinced Lee to trust his fourth pitch.

Contact staff writer Matt Gelb at mgelb@phillynews.com, or @magelb on Twitter