KANSAS CITY, Mo. — This was the type of confidence-boosting series the Mariners had long hoped their young hitters could grab hold of before it was too late.

For all the talk of sending young bats to the minor leagues to straighten things out, the Mariners accomplished the equivalent in four games against two Kansas City Royals starters no longer in the majors and a third on his way back to Class AAA any minute now. The biggest beneficiary of all the pitching charity might have been Jesus Montero, who collected three more hits in a 6-1 win on Thursday as his team jumped on AAA call-up Will Smith early.

Montero hit a solo home run, a double, single and a sacrifice fly to equal his career high with four runs batted in. He also finished the series with 10 hits — matching his total output of the previous month — as the Mariners scored 31 runs in the four games, winning three of them.

"It means a lot, because I helped the team win," Montero said. "We scored six runs and four of those were mine. But I'm swinging at the bat well and seeing the ball well. ... I'm just trying to swing and see what happens."

The latest scoring outburst by Seattle on the road, in front of 16,706 fans at Kauffman Stadium, provided a much-needed tonic for a young group of hitters trying to work their way out of prolonged slumps.

Seattle's early-scoring offense also helped Mariners ace Felix Hernandez roll to a relatively easy win. But Hernandez did experience a few challenges during his eight-inning stint on a day that began with a 98-degree temperature that climbed to 102 by the end.

The Royals piled up four hits the first two innings, but Hernandez erased the runners on a pair of double-play grounders. He threw just 65 pitches the first seven innings, then needed 24 to escape the eighth after the Royals, down by four, loaded the bases with one out.

Hernandez struck out Alcides Escobar, then got the dangerous Billy Butler to ground into a fielder's choice to end the home side's final threat. Hernandez barely used his sinker, instead using his four-seam fastball to keep getting grounders.

"I knew it was hot, so I was just trying to throw strikes and get some quick outs," Hernandez said. "I was throwing a lot of fastballs because I realized they were sitting on my changeup and breaking pitch with two strikes. So, I started throwing my fastball."

In the meantime, the Mariners got the early jump on Smith, the latest Royals left-handed starter pressed into emergency service fresh from Class AAA. On Tuesday, the Mariners had blitzed AAA lefty Ryan Verdugo for six runs in 1-2/3 innings before he was dispatched back to the minors the next day.

Verdugo had been called up after Seattle scored seven off Royals lefty Jonathan Sanchez in 1-1/3 innings of the series opener. The Royals designated Sanchez for assignment the following day.

Montero didn't even realize his second-inning homer off Smith on Thursday had cleared the yard. Royals center fielder Jarrod Dyson was so busy racing back for the ball that he lost track of the wall and collided with it — while the ball easily cleared the fence.

Dyson fell to the ground but was otherwise fine in a rather comical moment.

"I saw the guy lying down on the ground," Montero said. "I looked for the ball and it was like, 'Oh, it's a home run, wow.' "

The M's added two more runs that inning, and Montero singled in the fifth to drive in another for a 4-0 lead. The Royals countered with their only run of the game on an Eric Hosmer double and a Chris Getz single in the bottom of the frame.

The run snapped a scoreless innings streak of 19-2/3 produced by Hernandez.

But that would be it for the Royals, who saw Montero double home Casper Wells in the seventh to make it 5-1. Montero came up one final time in the ninth needing a triple to hit for the cycle, but settled for a sacrifice fly and his fourth RBI.

Mariners manager Eric Wedge was pleased to see Montero and some of his other young hitters gain some confidence here.

"It was a great series for us. I love the way we played," Wedge said. "You talk about a vision of the way you want your team to play and how you want to go out there and play major-league baseball, this was about it. This is what we're looking for."