Miami entered the series having not scored in 37 innings, but it is the Rockies who have struggled for runs in the first three games. They managed one Monday, two against Jose Fernandez on Tuesday and two more against Jacob Turner on Wednesday.
De La Rosa (10-5) made sure the two runs would stand up with another strong performance, and the bend-not-break bullpen helped Colorado snap a two-game skid.
De La Rosa pitched out of trouble when Miami had runners on first and third in the first and second innings. After Turner singled in the second, De La Rosa set down 13 of his last 15, yielding only two-out singles to Adeiny Hechavarria in the fifth and Placido Polanco in the sixth.
He allowed six hits and struck out four to reach double-digit victories for the first time since winning 16 games for the Rockies in 2009.
Turner (3-3) was a hard-luck loser for the second straight outing. He allowed two runs and six hits, struck out four and walked two in six innings. It was the third straight start he allowed just two runs.
Colorado went ahead in the second. Helton reached on a two-out double down the left-field line and scored on Nolan Arenado's single to left to make it 1-0.
DJ LeMahieu gave the Rockies a 2-0 lead in the fifth with a sacrifice fly to centre to score Yorvit Torrealba.
The Marlins wasted a chance when they loaded the bases with no outs against reliever Edgmer Escalona in the seventh. Escalona struck out Hechavarria looking for the first out, then Josh Outman came on and fanned rookie Christian Yelich for the second out.
Miami broke through in the eighth when Polanco scored on Donovan Solano's third single of the night. The Marlins threatened for more, but Matt Belisle struck out pinch-hitter Justin Ruggiano with runners on first and second to end the inning.
NOTES: Helton's double was the 579th of his career and moved him past Wade Boggs on the career list. ... Stanton is hitting .314 with seven home runs in 10 career games at Coors Field. ... LeMahieu has hit safely in all five games he has played since the All-Star break. ... Colorado's Juan Nicasio (6-4) will face Nathan Eovaldi (2-1) in the final of the four-game series Thursday afternoon.