Tatis hit a 477-foot homer, the longest of his career and his NL-leading 21st. He also doubled, but the Padres lost for the 13th time in 17 Giochi.
The gametime temperature was 99 degrees at Coors Field, and the hot weather contributed to a big offensive day. The teams combined for five home runs and 23 hits and neither starter made it out of the fourth inning.
After an error in the ninth inning helped the Padres score a run that made it 7-all, the Rockies won it. Trevor Story drew a leadoff walk from Austin Adams (2-1), stole second and scored when Blackmon hit a 1-2 pitch into center field.
Story doubled twice, stole two bases and scored three times.
Raimel Tapia had three hits to extend his hitting streak to 13 Giochi, the longest of his career, and C.J. Cron homered for the second time in the series for the Rockies.
The Rockies led 7-6 in the ninth, but Carlos Estévez (2-0) walked the first two batters in the ninth and second baseman Brendan Rodgers’ throwing error allowed the Padres to tie it on a sacrifice fly.
Colorado starter Kyle Freeland gave up two homers in 3 2/3 innings and has allowed nine longballs in his last three starts.
Tatis hit a solo drive and Trent Grisham had a two-run homer in the third to make it 3-all. he Padres went ahead 5-4 in the fourth on consecutive doubles from Tatis and Manny Machado.
Elías Díaz had three hits, including a home run off San Diego starter Blake Snell.
Pinch-hitter Jake Cronenworth homered for the Padres.
Montagne Rocciose: RHP Jon Gray (right flexor tendon) will throw a bullpen session on Thursday instead of a simulated game.
The Padres optioned LHP Ryan Weathers to Triple-A El Paso and recalled RHP James Norwood. Norwood made his San Diego debut by getting the final two outs of the fourth inning.
AVANTI IL PROSSIMO
padri: RHP Joe Musgrove (4-6, 2.50 ERA) will open a four-game home series against Cincinnati on Thursday night.
Montagne Rocciose: RHP Germán Márquez (4-6, 4.60) makes his sixth career start against Milwaukee on Thursday night in the opener of a four-game home series.