WASHINGTON -- Nolan Arenado was a little bummed when he pulled into third base in the top of the fifth inning.
His fly ball to right was dropped by Bryce Harper - who lost the ball in the sun - and was originally ruled a three-base error.
"It looked like he had some trouble with the sun. I was a little bothered by it," Arenado said of the error call.
But the call was later changed to a triple and that was fitting for Arenado, who had little go wrong Sunday afternoon as he went 4-for-4 with three RBIs as the Colorado Rockies beat the first-place Washington Nationals 5-3.
Arenado, who tied a career high for hits in a game, is now batting .552 in the last seven games and he leads the majors with 31 RBIs this month. His first three hits came against top prospect Lucas Giolito, who was making his fourth career start but appeared to lose some velocity Sunday as opposed to previous outings.
"Obviously in the reports we were reading he throws 95 to 97 (miles per hour). On video (Sunday) it wasn't that," Arenado said. "With his length the ball gets on you. It is not a comfortable at bat, I will say that. It is not comfortable."
"In the first inning he was getting behind a little bit," Arenado added. "As the game went on he settled in a little bit. He looks like he is going to be a good pitcher. His curveball is pretty sharp. When I was guessing I was guessing right."
Chad Bettis (11-7) leads the Rockies in wins after he struck out six with one walk while throwing 106 pitches. He gave up just two runs in seven innings.
"It was fun today. Everything was working," Bettis said.
Rockies manager Walt Weiss was also pleased.
"I really liked his changeup today," Weiss said of Bettis. "I always thought his changeup was a real good weapon. He used it well today. I thought he put it all together."
Logan gave up a homer to Harper in the ninth, making it 5-3. That brought in reliever Adam Ottavino, who recorded the last three outs.
"We hit some balls hard," said Washington manager Dusty Baker, whose team has now six of its last eight.
The Rockies got a strange insurance run in the top of the eighth to make it 5-2. Daniel Descalso, who had doubled, scored from second on a wild pitch from Koda Glover when his offering hit home plate umpire Mike Muchlinski in the shoulder and bounced away from catcher Wilson Ramos.
"That last one really hurt," Baker said of the fifth run by the Rockies. "The ball hit the umpire. It could have been a one-run game."
Ramos, who had two hits, blasted the first pitch from Bettis in the seventh to trim the lead to 4-2. It was the 20th homer of the year for Ramos.
The Rockies scored three runs in the third to take a 4-1 lead.
Carlos Gonzalez had a two-out single and Arenado followed with a two-run homer just over the fence in left. It was the 35th homer of the year for Arenado.
On the next pitch, David Dahl hit another homer off starting and losing pitcher Lucas Giolito (0-1), who was making the fourth start of his major-league career and first since July 24. Giolito allowed four runs and six hits with two walks and two strikeouts in five innings.
"The future is bright, for sure," Weiss said of Giolito. "Big kid, big-time arm. He showed a really good breaking ball and threw some good change ups to go with a power fastball. I have heard a lot about him and for good reason."
The Nationals tied the game at 1 as Turner (two hits) led off the last of the first with a solo homer to left.
Arenado had an RBI single in the first to give Colorado a 1-0 lead.
Bettis escaped a jam in the last of the fifth when speedy Ben Revere hit into a double play with runners on first and third to end the inning.
"That was a game changer," Weiss said.
The Rockies (62-68) are 4-2 this year against the Nationals (75-55), who began the day eight games ahead of the Miami Marlins.
Washington first baseman Ryan Zimmerman ended the game with a flyout to right as Ottavino got his second save.
"It was a small glimpse of what he can do," Bettis said of Ottavino.
Descalso had two doubles for the Rockies, who host the first-place Los Angeles Dodgers on Monday. "We are competing against a high level against these good teams," Arenado said.
NOTES: The Nationals called up RHP Lucas Giolito from Triple-A Syracuse to make the start Sunday. To make room on the 25-man roster, INF Wilmer Difo was sent to Double-A Harrisburg after he hit .257 (9-for-35) in 18 games at the big league level this year. ... Rockies RHP Jon Gray (8-6, 4.61 ERA) will start on Monday against the Dodgers RHP Kenta Maeda (13-7, 3.37 ERA) in Denver. ... Washington begins a series on Monday in Philadelphia with RHP Tanner Roark (13-7, 2.99 ERA) going against Phillies rookie RHP Jake Thompson (1-3, 9.78 ERA). ... Washington LF Jayson Werth got a break from the starting lineup Sunday as OF Ben Revere made the start in left and batted second. Werth has reached base in 53 of his last 54 games. Werth and Revere are both former outfielders for the Phillies.