Seattle Mariners ace Luis Castillo was impressive on the mound Saturday against the Pittsburgh Pirates. He went six innings, giving up zero runs on one hit and striking out ten batters.He had complete control of the strike zone all game. Castillo threw 96 total pitches, and 64 of those were for strikes. The start has dropped his ERA down to 2.69 on the season.Seattle Mariners@MarinersWelcome to the School of Rock.1304109Welcome to the School of Rock. https://t.co/0tmq1t7lJSIt's an impressive start, even if Pittsburgh is starting to slump after their red-hot streak. Four pitchers were used in relief for Seattle, and all did their jobs to keep the shutout intact.On the offensive side of the ball, Seattle shined. Their top three hitters all had two hits apiece. Only one Seattle player failed to get a hit in their dominant performance on Saturday."He's the ace for a reason" one fan tweeted.JakeFromStateFarm206@statefarm_206@Mariners He's the ace for a reason4@Mariners He's the ace for a reason"What a stud!" another fan tweeted.Seattle Spectre@seattle_patriot@Mariners What a stud!@Mariners What a stud!Stephen Lylyk@LylykStephen@Mariners I enjoyed la Piedra day5@Mariners I enjoyed la Piedra dayChris Arneson@ArnePodElectric @Mariners twitter.com/Mariners/statu…Seattle Mariners@MarinersWelcome to the School of Rock.1324111Welcome to the School of Rock. https://t.co/0tmq1t7lJSElectric⚡️⚾️ @Mariners twitter.com/Mariners/statu…Seattle Mariners fans are ecstatic with how Luis Castillo performed. He was nearly perfect on the mound, as he had great control of his pitches and looked sharp.Go-Cart Mozart’s Weather Chart@sam_hates_musicLuis Castillo is good at baseball. twitter.com/mariners/statu…Seattle Mariners@MarinersWelcome to the School of Rock.1330112Welcome to the School of Rock. https://t.co/0tmq1t7lJSLuis Castillo is good at baseball. twitter.com/mariners/statu…Eric Yang@itsericyangNumber 1 starter. twitter.com/mariners/statu…Seattle Mariners@MarinersWelcome to the School of Rock.1331112Welcome to the School of Rock. https://t.co/0tmq1t7lJSNumber 1 starter. twitter.com/mariners/statu…🖤@coltonwooten11HIM twitter.com/Mariners/statu…Seattle Mariners@MarinersWelcome to the School of Rock.1333112Welcome to the School of Rock. https://t.co/0tmq1t7lJSHIM twitter.com/Mariners/statu…Tobacado@TobacadoFantastic last 2 outings for La Piedra after a rough month of outings. That's how a true Ace bounces back. Doesn't let the bad get to them, continues to improve, and gets back in the groove. twitter.com/Mariners/statu…Seattle Mariners@MarinersWelcome to the School of Rock.1334112Welcome to the School of Rock. https://t.co/0tmq1t7lJSFantastic last 2 outings for La Piedra after a rough month of outings. That's how a true Ace bounces back. Doesn't let the bad get to them, continues to improve, and gets back in the groove. twitter.com/Mariners/statu…Fans are impressed that Castillo has bounced back from starting the season off wobbly. He's done nothing but shove on the mound since then, looking like a true ace.Seattle Mariners need the American League West to cool offPittsburgh Pirates v Seattle MarinersThe Seattle Mariners are starting to put it together after an underwhelming start to the season. Saturday's win improves their record to 27-25, just one game behind the Los Angeles Angels.They would love to see the Texas Rangers stumble. The team has been red-hot lately and holds a 6.5-game lead over Seattle. It's unlikely that Texas will struggle in their next series as they play the Detroit Tigers.Seattle and Texas face off in a three-game series to start June. This will be the Mariners' chance to gain some ground.The Mariners need to keep up the momentum they've built recently. They swept the Oakland Athletics earlier in the week and took a game from the Atlanta Braves before that.This team has a talented roster capable of competing with the best. Players like Julio Rodriguez and Luis Castillo have the talent to take this team far.It'll be interesting to see if this team can climb up a tough AL West division. Four teams in that division look like playoff contenders, and It may be a battle all season long.