DENVER -- Todd Helton’s first 300 homers were gratifying No. 301 topped them all.

The Colorado Rockies star, who finally knows what a playoff race feels like, came through with the one of the most meaningful swings of his stellar career Tuesday night.

The Rockies were down to their last strike when Helton hit a two-run homer off Los Angeles closer Takashi Saito in the ninth inning to give Colorado a stunning 9-8 victory and a doubleheader sweep of the dejected Dodgers.

“I don’t know when I’ll come off of that high. Just to be in that moment was unbelievable,” said Helton, who sprinted around third base like a little kid being called in for dinner and dived into the pile of jubilant teammates awaiting him at home plate.

“It’s one of my favorite moments ever just watching him come around third,” teammate Matt Holliday said.

The Rockies won the opener 3-1 behind Jeff Francis, who struck out a career-high 10 batters in his 16th win. The teams played a split doubleheader to make up for a rainout on July 27 at Coors Field, and both clubs looked at it as crucial to their hopes of catching San Diego in the NL wild card chase. The Dodgers began the day three games behind the Padres and are now 4½ back, same as Colorado.

“That was a tough one for us,” Dodgers manager Grady Little said. “I think our playoff chances went out today in Coors Field.”

Saito (1-1) had converted 16 straight saves and 39 of 42 chances this season, including all five against the Rockies, who hadn’t gotten a hit off him in six combined innings until Holliday punched a single to right with two outs to bring up Helton.

The slugger who has toiled for more than a decade in Denver with nary a sniff of a playoff chase until this year followed with his fifth career game-ending homer, sending one of Saito’s nasty sliders into the seats in right-center.

“I went with my strength,” Saito said through a translator. “I’m discouraged. I’m disappointed.”

Helton has been waiting for a moment like this.

“Oh yeah, just to be in a situation where a game matters,” he said. “When you hit a home run and the game doesn’t matter, you sort of run the bases and give your teammates high-fives. But when you’re in a situation like that, why do you want to try to keep your emotions in? I mean, it’s an amazing win for us.”

His teammates enjoyed it, too.

“That’s as good as it gets for me,” manager Clint Hurdle said. “I was happy for Todd, I was happy for us. I’ve watched Todd play a long time. I’m proud of him. I’m happy for him. He’s found another gear this month.”

Helton is hitting .423 with a .538 on-base percentage, two homers and 10 RBIs in 15 games in September.

Little just looked away when he saw Helton get hold of Saito’s last pitch.

I didn’t watch it,” he said. “I didn’t have to. I knew it was leaving the park.”

Holliday hit his 33rd homer earlier in the game. It was his 200th hit this season and the 100th homer of his career.