Bryce Harper executes a take-out slide of Colorado’s Marco Scutaro in an attempt to derail a double play in the fourth inning Friday as the Nats’ four-game winning streak comes to a halt. (Rob Carr/Getty Images)

Stephen Strasburg will not have to wait long to climb a mound again, only until Tuesday in Kansas City at the All-Star Game. The one-inning appearance will not only cement his rightful place among the best pitchers in the game, but also may serve as a helpful diversion. Until he makes his first start of the second half for the Washington Nationals, the first losing streak of his career, and the two pitches Friday night that led to it, will stay on his mind.

Strasburg suffered his third consecutive loss Friday night as the Colorado Rockies beat the Nationals, 5-1, ending his stirring first half of his season — and halting the Nationals’ four-game winning streak — on a sour note at Nationals Park. He gave up three runs, two of them earned, on eight hits and a walk, striking out six, as Rockies left-hander Drew Pomeranz stifled a previously scalding lineup.

“It’s not a good feeling, but what can you do?” Strasburg said. “You can only go out there and give it everything you have. Sometimes it’s not going to work out.”

Strasburg showed no ill-effects from his previous start, when Atlanta’s wicked heat forced him out of the game after three innings. He received an IV in the afternoon and drank more fluids. Pitching at night, even with a 96-degree temperature at first pitch, Strasburg did not feel hot during the game.

Strasburg found a new nemesis. Rockies first baseman Tyler Colvin became the first hitter to whack two homers off him in the same game, driving in all three runs against Strasburg. Colvin joined Atlanta Braves second baseman Dan Uggla as the second to hit multiple home runs off him, period.

“All I can really think of is two pitches,” Strasburg said. “I don’t think they were the right pitches to throw in that situation. I feel like I didn’t have the right mind-set, so it should be an easy fix.”

Colvin had not faced Strasburg before, and then he drilled hits in all three of his at-bats, also becoming the seventh batter with at least three total hits off Strasburg. In the eighth, off reliever Ryan Mattheus, Colvin smashed a drive to the right field warning track and missed a three-homer game by a few feet.

Aside from Colvin’s missiles, the Rockies took advantage of good fortune and late jumps by outfielders. Their other six hits off Strasburg were singles, two of which fell just shy of Michael Morse after he picked up the ball a moment late.

The Rockies did not blister the ball against Strasburg, but they made him throw 107 pitches over six innings.

They also left him to swallow a hard-to-fathom fact: In their last 11 games, the Nationals are 7-1 when Strasburg does not start and 0-3 when he does.

Manager Davey Johnson plans to schedule Strasburg’s first start after the all-star break depending on the workload in the game.

The Nationals had scored at least five runs their past eight games, averaging 9.4 runs during that span. And then Pomeranz, a 23-year-old with two career wins, dominated them, basically, with one pitch.

“I think a lot of guys are going to go home dreaming about fastballs tonight,” shortstop Ian Desmond said. “We just missed a bunch of balls.”

Pomeranz allowed no runs over 61 / 3 innings and, really, he could have given up no hits. The Nationals’ only knock against him came in the fourth inning, when Bryce Harper lofted a bloop into shallow center field and the Rockies’ miscommunication led to the ball hitting the turf.

In the first inning, the Nationals watched Pomeranz bounce several breaking balls in the dirt. “Everybody in the ballpark knew he couldn’t get his breaking ball over from the first inning on,” Johnson said. “It was just fastball-cutter. Sometimes when you know what’s coming, you’re a little overly aggressive.”

Pomeranz cruised with an astonishing pitch selection: He threw 74 fastballs out of his 81 pitches, some straight and some cutters. The Nationals hit four infield popups. Morse walked back to the dugout once with nothing but a knob in his hands.

“Just an off night all the way around,” first baseman Adam LaRoche said, standing in a quiet Nationals clubhouse. “I think everybody in here got pitches to hit. We did nothing with it. He would cut a few. It had a little action, pretty good velocity. But nothing we haven’t seen before.”

The only thing that stopped Pomeranz was the Rockies’ recently implemented 75-pitch limit for their starters, which they instituted to support a new starting rotation format. Ryan Zimmerman launched a home run off reliever Rex Brothers to lead off the ninth to prevent the Nationals’ second shutout this season.

Behind Colvin, though, the Rockies had already built a comfortable lead. In his first at-bat, with one out in the second inning, Colvin popped the first pitch foul behind home plate. Catcher Jesus Flores shuffled back to catch the routine out, but the ball plopped out of his glove. The gaffe gave Colvin new life. Strasburg got Colvin to whiff at a change-up, and 0-2 is usually a death sentence for hitters against Strasburg.

The baseball gods have a twisted sense of justice, though, and they did not forgive Flores’s bobble. Strasburg tried to bury Colvin with a 97-mph fastball, and Colvin rocketed one of the hardest-hit balls of Strasburg’s career to right field. The blast nearly scraped the third deck. The Rockies led, 1-0.

“Dumb pitch,” Strasburg said. “I spiked a change-up and he swung at it. You got a guy with some power up there, that’s the last two you want to do, try and throw an elevated fastball and miss down in the zone a little bit, right into his swing plane.”

Strasburg returned to his typical dominance, striking out the side in the second inning. By the end of the second he had already induced seven swings and misses, at least one with all three of his pitches.

In the fourth, Strasburg walked Carlos Gonzalez to lead off the inning. With one out, Colvin came to the plate again. He battled through eight pitches until Strasburg threw a 3-2, 88-mph change-up. The pitch stayed just high enough for Colvin to lace into the seats above the right field scoreboard, and the Rockies led, 3-0.

The Nationals had overcome deficits of at least three runs in two straight games, but not Friday night. Their bullpen yielded two runs to widen the gap, and they could not solve Pomeranz. And so Strasburg had to absorb another loss, with too much time to think about it.