PHILADELPHIA -- Less than two months into the season, Colorado Rockies center fielder Charlie Blackmon is making a case that he is the best leadoff hitter in baseball.

"If you look at guys from around the league, there are different styles of leadoff hitters, but man, it's hard to argue against what he's doing out of that spot," Rockies manager Bud Black said after watching Blackmon swat a pair of two-run home runs in an 8-2 win over the floundering Philadelphia Phillies on Tuesday night at Citizens Bank Park.

"He's been swinging the bat good all year and, getting to know him and the preparation he puts in, it doesn't surprise me."

Gerardo Parra added a solo home run and rookie right-hander German Marquez (3-2) scattered seven hits in six innings for the Rockies, who have won seven of their last nine to improve to 30-17, tops in the National League.

Zach Eflin (0-2) gave up eight runs and 10 hits in six innings for the Phillies (15-28). Philadelphia has dropped 19 of its past 23 games and has managed just three runs in the past three games.

"When he struck out Blackmon in the first inning with that two seamer, it looked like it had great movement and I thought we were in for a good outing from him," Phillies manager Pete Mackanin said of Eflin. "Thereafter, he just couldn't keep the ball down. He hung a breaking ball for the home run and got another fastball up for a home run. You've got to pitch down in the zone and know (if you don't) you are going to get hurt."

Andrew Knapp hit a solo home run for the Phils in the ninth inning.

Blackmon leads all leadoff hitters with 62 hits, six triples and 40 RBIs, and among center fielders, his 11 home runs are second only to the Angels' Mike Trout (14). He is batting .325 with a .618 slugging percentage.

In his past 10 games, Blackmon is 19-for-43 (.442) with three homers and 13 RBIs.

"I feel like I've been getting a lot of hits lately on really tough pitches," Blackmon said. "Today I hit a couple mistakes."

Eflin came into the game looking for his first win in seven starts, but the long ball did him in.

After retiring six of the first seven batters he faced, Eflin opened the third inning by walking catcher Tony Wolters. Two batters later, Blackmon drilled an 0-1 breaking ball into the seats for his 10th home run and a 2-0 lead.

"For me, if you hang a curveball over the middle, those are easier to hit than fastballs," Blackmon said.

The Phillies scratched out a run in the bottom of the third when Marquez hit Tommy Joseph with an 0-1 pitch to load the bases, then walked Andres Blanco to give Philadelphia its first run.

Colorado broke through in the fourth inning. After Parra and Alexi Amarista delivered RBI singles and Wolters pushed home another run with a groundout to give the Rockies a 5-1 lead, Knapp went to the mound to talk with Eflin.

Four pitches later, Blackmon hammered another Eflin pitch into the seats for his first multi-home run game of the season and the eighth of his career -- three of them coming at Citizens Bank Park.

Mackanin, who has already overused an ineffective bullpen this season, left Eflin in the game for another two innings and saw him surrender a solo home run to Parra in the sixth inning.

"It's frustrating, but it happens," Eflin said. "It's baseball. There are going to be a lot of times in my career when I give up a lot of hits and a lot of runs. But I'm really not worried about it right now."

Making his first career start against the Phillies, Marquez allowed one earned run for the second straight outing. In three starts on the road this season, he has allowed just two earned runs in 17 innings.

"Starting pitchers are going to be stressed at least one time every game and German got the outs and made the pitches he needed," Black said.

Marquez benefited from another offensive outburst by the Rockies, who have reached double-digit hits in five straight games.

"I felt pretty good," Marquez said through an interpreter. "At times I had to battle with my command, but I made big pitches when I had to and gave my team a chance to win. They gave me some breathing room and a cushion to go out there and not try to be perfect."

NOTES: The Rockies reinstated SS Trevor Story from the 10-day DL. To make room for him, RHP Jeff Hoffman was returned to Triple-A Albuquerque. Story, 24, was placed on the DL on May 11 with a strained left shoulder. In four rehab games with Albuquerque, Story went 3-for-11 with one home run. Hoffman, 24, was recalled before Monday's game against the Phillies and picked up a victory in his second start of the season, limiting the Phils to one run and three hits and getting seven strikeouts in seven innings. ... The Phillies have played the fewest home games in the National League (18) and the second fewest in baseball, ahead of only the Chicago White Sox. ... RF Aaron Altherr picked up two more hits and is the first Phillies player with 19 or more extra-base hits in his first 35 games of a season since Chase Utley in 2014.