Saturday against Cincinnati, it was his fielding that stole the show.
Span made pair of impressive catches to halt Reds rallies, Harper hit a two-run homer and scored twice, and Dan Haren had his best start of the young season as the Nationals beat the Cincinnati Reds 6-3.
Span and Jayson Werth each had two hits for Washington, which has won the first three games of the four-game set. Harper's two RBI gave him 18, a Nationals record for April.
"[We were] two hits away, had it not been for Span, from tying that game up or even going ahead," Reds manager Dusty Baker said. "Those were two heck of a plays. Very rarely do you see two Web Gems in one game."
Trailing 6-2 in the seventh, the Reds got a two-out RBI single from pinch-hitter Todd Frazier off Tyler Clippard to make it 6-3. Shin-Soo Choo then walked to load the bases and Zack Cozart hit a laser to left-center, but Span's running catch ended the threat.
"I didn't think he had a chance to outrun that ball. He outran it. When [Cozart] hit it, I thought `that's going to score three,"' Washington manager Davey Johnson said.
In the sixth, after Choo homered to lead off and Cozart singled, Span thwarted the rally when he raced to the wall in left-center and made a leaping catch to take at least an extra-base hit away from Joey Votto.
"I got a great jump on both of those balls," Span said. "On Votto, I was already playing deep, respecting his power. I'm not sure if the ball would have went over, but I was prepared to bring it back if it did go out."
Haren (2-3) didn't quite match Jordan Zimmermann's one-hitter and Gio Gonzalez's impressive eight innings of one-hit ball the previous two games, but he was sharp enough. Haren allowed two runs and six hits over six innings.
"That was more like him. He's still throwing with velocity, but he just changes speeds, moves the ball around, pitches," Johnson said.
Haren, who was roughed up by Cincinnati for six runs and nine hits in four innings of a 15-0 loss on April 5, lowered his ERA from 7.36 to 6.29 in his longest outing of the year.
"I finally feel like part of the team," said Haren, who was signed as a free agent this past offseason. "I've got to be like this or better the rest of the year. There's no excuse for me not to be."
Rafael Soriano pitched a scoreless ninth for his seventh save.
Brandon Phillips had three singles for Cincinnati, which has lost four of five.
Reds starter Mike Leake (1-1) gave up four runs, three earned, in three innings.
The Nationals scored twice in the second. Ian Desmond and Anthony Rendon drew one-out walks. Kurt Suzuki popped out, but Haren blooped a single into short right field scoring Desmond. Rendon went to third and scored when Span singled.
Harper and Werth opened the third with singles and, after Adam LaRoche flied out, Desmond singled, scoring Harper. Leake fanned Rendon, but Suzuki hit a grounder toward the hole between third and shortstop. Third baseman Jack Hannahan made a diving stop, but threw wide to second and Werth scored as the ball rolled into right field.
The Reds ended a 17-inning scoring drought in the fourth when Votto doubled and Phillips singled him home.
Harper, on the one-year anniversary of his callup, put the Nationals ahead 6-1 in the fourth, homering into the Washington bullpen on a 1-2 pitch off Alfredo Simon with Danny Espinosa on first. It was Harper's ninth of the season.
"And if you know him, he probably (thinks) he's having an off-year right now," Johnson said of Harper. "He expects lot of himself and that's a good trait."
- Reds LF Chris Heisey left in the third inning with a strained right hamstring.
- Nationals C Wilson Ramos, on the 15-day disabled list with a strained left hamstring, caught three innings and went 0 for 1 with a walk Friday night in the first game of a rehab assignment with Double-A Harrisburg. Johnson said Ramos will travel with the team to Atlanta Sunday. He's eligible to come off the DL Monday.. Johnson said 3B Ryan Zimmerman, on the DL with a left hamstring strain, will likely begin a rehab assignment Monday and rejoin the team Friday in Pittsburgh.
- Cincinnati LHP Chris Cingrani (1-0, 2.25) opposes LHP Ross Detwiler (1-1, 1.38) in Sunday's finale.