Nationals starter Erick Fedde allowed seven runs in his major league debut, but he threw first-pitch strikes to 18 of 22 Rockies, showing a fearlessness that might earn him another turn in the rotation. (Katherine Frey/The Washington Post)

Erick Fedde’s first major league start ended with a fidgety walk to the first base dugout after four grueling innings. The Colorado Rockies had not bowed to ceremony and scored seven runs against the rookie, who nevertheless did exactly what the Washington Nationals thought their top pitching prospect would. He attacked, forcing the Rockies to beat him. They did.

The Nationals never recovered from those seven runs and fell, 10-6, in the first game of a day-night doubleheader. They beat the Rockies, 3-1, in the second game as current fifth starter Edwin Jackson fended off his would-be challenger for a rotation spot, Fedde, with seven innings of one-run ball in which he walked two and struck out six.

While Fedde was not perfect, he did not crumble, and the Nationals did not have to scramble for a long man, using four relievers to leave four fresh arms for the nightcap. That left plenty of firepower to preserve Jackson’s gem, which Ryan Madson and Sean Doolittle closed out with a perfect inning each.

Fedde was the Nationals’ first-round choice in the 2014 draft and is the top-rated pitching prospect left in what was once a pitching-rich system. But the reason the Nationals felt they could part with last year’s much-heralded debutant, Lucas Giolito, is that they saw something in Fedde they did not see elsewhere. Something about his makeup, the cliched “bulldog mentality,” meant more than just the stuff. Mid-90s fastballs and good sliders are not hard to find these days.

Nationals third base coach Bob Henley congratulates first baseman Ryan Zimmerman after he hits his first of two home runs, making him the all-time leader for Washington players. (Katherine Frey/The Washington Post)

And as the Rockies found holes, benefited from close calls — and hit a handful of balls hard, too — Fedde kept challenging Rockies, showing no signs of any lapse because of disappointment.

That he allowed 10 hits and walked two in four innings meant his debut will not be listed with Stephen Strasburg’s among the Nationals’ all-time best. But the way he did it, with first-pitch strikes to 18 of 22 Rockies, with unrelenting defensive presence of mind — with a fearlessness to his confident tempo — nevertheless made an impression.

“I think what he gave us was better than what the results were,” Manager Dusty Baker said.

In his first time working through a major league order, Fedde threw first-pitch strikes to every hitter in the formidable Rockies lineup. After allowing two runs in the first, he struck out the side in the second, pouring in strike one, his fastball sitting from 94 to 96, his slider in the mid-80s. More balls found holes than found barrels, but enough found both to give the Rockies five earned runs in four innings.

“I’m definitely not happy with the results, but I felt like my stuff was pretty good,” said Fedde, who looked wide-eyed and unsatisfied after the game. “I guess a lot of balls landed in good spots for them, but it’s one where I still need to make better pitches and get better results.”

This season, as he moved from Class AA Harrisburg to facing more experienced opposition in Class AAA Syracuse, the Nationals wanted Fedde to learn to get outs in the strike zone. In Class AA, he got hitters with pitches out of the zone. More experienced hitters will not chase.

Veteran Edwin Jackson contributed seven innings of one-run ball in which he walked two and struck out six as the Nationals won the nightcap. (Mitchell Layton/Getty Images)

On Sunday, Fedde had no trouble getting ahead of Rockies hitters, even the all-stars at the top of the order. He did, however, have trouble burying them. Six times in the first four innings, Fedde got ahead of batters 0-2, then did not strike them out.

“Those guys are the best in the world for a reason, and it’s something I think I can do a better job at, executing two-strike pitches,” Fedde said. “It was something that hurt me today.”

So with the Nationals trailing 4-1 and two men on in the third, Ryan Zimmerman — the first draft pick in Nationals history, chosen nearly a decade before Fedde — homered to tie the game and became the all-time leader among Washington players with 238 homers, passing Frank Howard. Zimmerman homered again later, but the Nationals could not climb all the way back from the hole Fedde left. In fairness, far more experienced starters than he have struggled against the Rockies.

“If we had to pick a first time out for him, we probably wouldn’t have picked Colorado — that’s just how it was — because Colorado can hit,” Baker said. “. . . It was a tough assignment.”

Jackson, meanwhile, handled that assignment like the veteran he is. He worked through the Rockies’ lineup with ease, winning the everlasting battle with his command. His only lapse — a two-out walk to opposing starter Jon Gray in the fifth — resulted in a run. He did not allow another, which means the home runs Adam Lind and Brian Goodwin hit in the bottom of that inning stood up.

So after Fedde’s Game 1 loss and Jackson’s gem, the Nationals face a decision: Do they allow Fedde the opportunity to start again?

Fedde’s spot in the rotation technically belongs to Strasburg, who is eligible to return from the disabled list Thursday. But Baker said he is not sure whether the Nationals will bring Strasburg back right away, though they initially said he would miss just one start because of the nerve impingement in his elbow.

Strasburg “said he’s feeling pretty good. We want him to feel great,” Baker said. “Right now we don’t know.”

Jackson, who turned in his second excellent outing in three Nationals starts, seems to have a hold on the fifth spot in the rotation for now. The Nationals will have to rejigger their rotation in the days to come, regardless of Strasburg’s status. Because of the doubleheader, none of the starters on their big league roster will be on full rest for Wednesday’s game.

However they configure it, Sunday ended up as something of a showcase. Fedde showed the Nationals enough to encourage them about what he might be able to bring in the future but also fostered uncertainty about what he is now. Jackson gave the Nationals exactly what they needed Sunday evening and continues to pitch his way into their plans for the immediate future.