ATLANTA -- The Braves' lineup is hard to keep in check or in the ballpark. Kansas City reliever Kelvin Herrera certainly found that out Tuesday night.
Jason Heyward, Justin Upton and Dan Uggla blasted home runs in the eighth inning, and the Braves ran their winning streak to 10 games with a 6-3 interleague victory over the Royals.
The home runs, all off Herrera, came within a span of four batters and gave the red-hot Braves five home runs for the game. Juan Francisco had homered twice earlier off Kansas City starter Jeremy Guthrie.
Heyward hit his second of the season with one out in the eighth to break a 2-2 tie, and Upton made it consecutive homers with his eighth of the year. Then Uggla connected with two outs for his third homer of the season.
"We knew coming in that they had a lot of power," Royals manager Ned Yost said. "It went on display tonight."
Herrera's fastball reaches the high 90s and the homers he allowed left Turner Field about as fast. Heyward hit a 98-mph pitch to the opposite field and Uggla's homer came off a similar pitch. Upton's blast came on a changeup.
"His location wasn't very good," Yost said. "A lot of pitches were up and kind of down the middle. He hung a changeup for a homer. But Kelvin's been almost unhittable all year long."
"For me, those are some great hitters over there," Royals right fielder Jeff Francoeur said. "But I don't know if (Herrera's) tipping pitches or what, but they got to him tonight."
The Braves have made a lot of pitchers pay this season.
"I've never been part of anything like this," Upton said. "From top to bottom in our lineup, everyone can go deep."
"You know the power is there," Braves manager Fredi Gonzalez said. "It's nice to have that type of arsenal that can turn a game around quick."
The Braves can match their 13-1 start of 1994 with a victory over the Royals on Wednesday in the finale of the two-game series and their 10-game winning streak is the longest since a record 15 games in a row in 2000.
Chris Johnson drove in the fourth run of the inning with a single as the Braves improved to 12-1.
Although he didn't get the decision, Braves starter Kris Medlen allowed just six hits and two runs (one unearned) in seven innings. He struck out five, walked none and threw 73 of his 99 pitches for strikes.
Guthrie was just as good, giving up five hits and two runs in his seven innings. He struck out six, walked one and threw 61 of his 91 pitches for strikes.
But Herrera, who hadn't allowed a run over 5 1/3 innings in six previous outings, was no match for the Braves' power hitters in the eighth. He was also charged with the fourth and final run of the inning when Aaron Crow gave up an RBI single to Chris Johnson.
The game wasn't all good news for the Braves, though.
Luis Avilan came in after Eric O'Flaherty (who got the win) pitched a scoreless eighth inning and appeared to tear his left hamstring while pitching to his third batter.
"Obviously, the way he fell down, it doesn't look good," Gonzalez said. "I'm thinking worse case scenario.
Craig Kimbrel had to come in and got the final two outs around an RBI hit by Alex Gordon, who was 2-for-5 and has now hit in 12 straight games.
Francisco tied the game with his second homer off Guthrie and third of the season in the seventh, hitting a towering drive over the center-field fence off a fastball. But a strong throw from Francoeur kept the Braves from taking the lead in the inning.
Pinch-hitter Blake DeWitt followed Andrelton Simmons' two-out hit with a double off the glove of center fielder Lorenzo Cain. But Francoeur quickly retrieved the ball and threw a strike to catcher Salvador Perez, who had the ball waiting for Simmons.
Francisco had picked on an off-speed pitch from Guthrie for his homer in the second inning. But the Royals quickly got the run back in an unlikely way.
Chris Getz, who hadn't homered since July 19, 2009, pulled Medlen's misplaced 0-2 fastball into the right-field seats, not far from where Francisco's homer had landed.
It was just the third homer in 383 major league games for Getz and broke a drought of 954 at-bats. The second baseman had last hit a homer while with the Chicago White Sox against Guthrie, then with Baltimore.
An unearned run set up by third baseman Francisco's throwing error put Kansas City ahead in the fourth inning. Mike Moustakas singled with two outs and Francoeur did the same, driving in Perez.
NOTES: The two-game interleague series concludes with a 12:10 p.m. ET game Wednesday. Left-hander Mike Minor (2-0, 0.69 ERA) will start for the Braves against right-handed Wade Davis (1-0, 4.00 ERA). ... With both teams off on Monday, Jackie Robinson Day was observed on Tuesday, with everyone wearing No. 42 in tribute to the major league pioneer and Hall of Famer. ... With no designated hitter, Billy Butler started the game on the bench for the Royals. ... This is the second series that Kansas City pitchers have had to hit despite the season being barely two weeks old. The Royals played interleague games at Philadelphia on April 5-7. ... Royals manager Ned Yost spent Monday's off day on his farm in LaGrange, 75 miles southwest of Atlanta, doing some hunting and fishing.