Dominant early, Stephen Strasburg fell apart after one of Ryan Zimmerman's two errors and wound up dropping his fifth consecutive decision, an 8-2 loss Saturday to the Chicago Cubs, whose starting pitcher, Edwin Jackson, worked into the sixth inning and hit a two-run double for good measure.

Jackson (1-5) retired 12 of Washington's first 13 batters and allowed two runs and four hits in 5 1-3 innings. He earned his first win under a $52 million, four-year contract he signed after leaving Washington as a free agent, ended the Nationals' five-game winning streak.

Strasburg (1-5) set down Chicago's first 11 hitters, six via strikeout. But with two outs in the fifth, third baseman Zimmerman's off-target throw put a runner on. Turned out to be Strasburg's last inning, making for his shortest outing of 2013.

The NL All-Star's only win this season came April 1 on opening day against the lowly Miami Marlins, but he entered Saturday with a 3.45 ERA and was averaging 6 1-3 innings per start. This time, Strasburg needed 42 pitches in the fifth alone — and, to think, he actually got some defensive help before the problems arrived.

With one out in a scoreless game, Luis Valbuena laced a shot into the right-field corner for what should have been a stand-up double. Valbuena tried to stretch it into a triple and was thrown out at third, with right fielder Roger Bernadina hitting cutoff man Danny Espinosa, whose relay got there in time. Strasburg, backing up third base on the play, pumped his right fist to celebrate.

Moments later, his body language was rather negative, all slumped shoulders and bowed head.

The next batter, Welington Castillo, hit a grounder to Zimmerman, whose throw pulled first baseman Adam LaRoche off the bag (Zimmerman also made a fielding error in the seventh).

Strasburg followed with his first walk, to No. 8 hitter Darwin Barney, before serving up Jackson's two-out, full-count double to right-center that made it 2-0. That accounted for Jackson's first hit and RBIs of the season; he'd been 0 for 10.

Unraveling, Strasburg walked another batter and gave up Starlin Castro's single to load the bases. Anthony Rizzo grounded a single up the middle, the ball bounding into center to score two more runs. Instead of backing up home plate on the play, Strasburg ambled around on the infield grass and looked into the dugout.

All four runs were unearned, and Strasburg's ERA actually dipped to 3.10.

David DeJesus' two-run single was the highlight as Chicago scored four more in the sixth against reliever Zach Duke. Washington's lone lefty in the bullpen got only two outs and gave up four hits and a wild pitch. He also hit a batter.

Ian Desmond drove in both of Washington's runs off Jackson and had three hits — a homer, double and single — for the second game in a row. But it wasn't nearly enough to prevent Chicago from prolonging Strasburg's woes.