It was less than a week ago that we told you that the Kansas City Royals arms were in their finest form, as part of a 16-3 run that got them back into the AL Central and AL wild-card races.

Then came a three-game losing streak. But Friday served as a bounce-back day, with the team’s second-ever doubleheader sweep in Detroit and its first since 1984.

The Elias Sports Bureau noted that the six hits allowed by the Royals were the second-fewest they’ve ever allowed in a doubleheader (the fewest was five against the Milwaukee Brewers in 1977).

Elias also noted that it’s the fewest hits by the Tigers in a doubleheader in nearly 47 years. The last time they had six hits or fewer was Sept. 10, 1967, against the White Sox, a day in which they were no-hit in the opener by Joe Horlen.

With that bit of history out of the way, let’s take a look at the key performances for the Royals on Friday.

Hosmer with a little pop

Eric Hosmer became the first Royals player to homer in both ends of a doubleheader since Dean Palmer in 1998.

Longest Average HR in 2013

Minimum 10 HR

Hosmer’s homer in Game 1 was his first against Justin Verlander. His 29 at-bats against Verlander were his most against any pitcher without hitting a homer.

His homer in Game 2 was calculated at 424 feet by ESPN’s Home Run Tracker team.

The Royals' first baseman is averaging 422.2 feet per homer this season, the longest average home-run distance for anyone with at least 10 homers this season.

Hosmer has taken greater aim at hitting the ball in the air in the second half of the season. His ground-ball rate before the All-Star break was 55 percent. It’s 48 percent since then.

How they won: Danny Duffy

Making his second start after recovering from Tommy John surgery, lefty Danny Duffy allowed only one hit in six innings in Game 1.

Duffy averaged 93 mph with his fastball, down about one mile-per-hour from what it registered in his season debut. But the pitch was much more effective. He used it to retire 11 of 13 hitters, compared to his first start, in which his fastball yielded eight baserunners and netted seven outs.

How they won: James Shields

Shields continues to pitch at a high level. He threw seven scoreless innings and improved to 5-0 with a 1.93 ERA in his past eight road starts. He’s pitched at least seven innings and allowed three earned runs or fewer in each of his four starts against the Tigers this season. The Royals have won three of those four games.

Tigers hitters were 0-for-6 with runners in scoring position against Shields, with two ground outs, two pop outs and two fly outs fielded by a Royals defense that ranks second in the majors in Defensive Runs Saved.

Opponents are 3-for-32 against Shields with runners in scoring position over his past five starts.

Royals starters have now made seven straight starts of at least six innings. In those seven starts, they have combined to allow only nine earned runs in 46 innings.