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DENVER (AP) — Ian Desmond's throwing error in the seventh inning allowed Paul Phillips to score the go-ahead run, helping the Colorado Rockies to a 4-3 win over the Washington Nationals on Saturday night for a doubleheader sweep.

In the opener, Ubaldo Jimenez threw eight stellar innings in the Rockies' 6-2 victory.

Carlos Gonzalez and Seth Smith hit back-to-back homers for Colorado in the nightcap.

With the score tied in the seventh, Phillips led off with a single and was bunted to second. The backup catcher took third on a fly to center.

Smith sent a grounder up the middle that Sean Burnett (0-1) got a glove on, slowing it down for Desmond. But the shortstop's toss to first was low and Adam Dunn couldn't scoop the ball, allowing Phillips to score.

Colorado's Jason Hammel (1-2), who has been sidelined since April 27 with a strained right groin, went seven strong innings, giving up three runs and six hits.

Manuel Corpas pitched a perfect ninth for his first save in two chances. He was helped out by a diving stop by Todd Helton, who was back at first base after sitting out the opener with an illness.

Dunn hit a tying homer off Hammel in the sixth, his second solo shot of the doubleheader. Roger Bernadina also added a two-out, two-run double to left-center in the fourth.

Rookie Luis Atilano pitched five up-and-down innings for the Nationals, allowing three runs and four hits with four walks.

Gonzalez hit a two-run shot in the third that just curled inside the foul pole. Four pitches later, Smith followed with another drive to right.

Ryan Zimmerman finished the doubleheader with five hits, making him 13 for 25 this season against the Rockies.

Jimenez was at his best yet again earlier in the day, allowing just two runs and seven hits in his seventh win of the season, tying him for the major league lead.

The hard-throwing righty has been so good this season that his ERA increased after this gem. He entered with a 0.93 mark, only to see it climb to 1.12 — still the best in baseball.

The thing is, he doesn't really understand the fuss over his lively fastball or all the attention he receives after each start.

The ace doesn't really think he's doing anything that spectacular. Try telling that to the Nationals and the rest of the league.

"We got some good swings at what might be the Cy Young Award winner when you look up here at the end of the year," Washington manager Jim Riggleman said.

The Rockies needed a boost like this, especially after a rash of injuries to their starters.

They got Hammel back in the night game — pitching effectively, too — and Jeff Francis is scheduled to start Sunday, his first appearance on a major league mound since Sept. 12, 2008.

Livan Hernandez (4-2), who also has one of the better ERAs in baseball, matched Jimenez most of the way. He allowed three runs and seven hits in six innings.

Even he was gushing about Jimenez.

"He's the best pitcher in the game," said Hernandez, both of his losses coming against Jimenez. "He's unbelievable."

Jason Giambi and Miguel Olivo homered for Colorado in the opener, and Ian Stewart and Clint Barmes each drove in two runs.

NOTES: To make room for Hammel on the roster, Colorado placed infielder Eric Young Jr. on the disabled list with a stress fracture in his lower right leg. ... Washington has not allowed a first-inning run in its last 11 games. ... Nationals OF Josh Willingham wasn't in the starting lineup in either of the games after tweaking his groin two days ago. He did pinch hit in both games. ... After a few days of drizzle in Denver, the weather turned out to be cool but dry for both contests.