There's really only one thing Ke'Bryan Hayes or Dylan Carlson could have done in their respective first plate appearances of 2021 to build any more excitement for the rookie-year campaigns that began Thursday.

They both did it.

Pittsburgh's Hayes, the No. 9 overall prospect, and St. Louis' Carlson, No. 13, each kicked off Opening Day with a first-inning home run. Each boasts rarified hit tools, and each comes into the new season already bearing the expectation that he'll be a leading candidate for National League Rookie of the Year honors.

The top Pirates prospect hammered a 2-1 changeup from Cubs right-hander Kyle Hendricks well into Wrigley Field's bleachers in left-center field to give his club a two-run lead out of the gate. It left his bat at 105.3 mph and traveled a Statcast-estimated 410 feet to set the tone in Pittsburgh's 5-3 win. Hayes, who finished 1-for-5, swatted five homers while batting .376 over 24 Major League games last year and hit .431 with 10 extra-base hits over 17 Spring Training games this year.

“I felt like I couldn’t have squared it up any better,” the 24-year-old third baseman told MLB.com of his Opening Day shot. “I was a little out front, but I squared it up pretty good, so I knew it was going to go out.”

The Cardinals' top prospect, batting seventh, was not a sure bet to get an at-bat in the first inning, but was ready when it came. Carlson, 22, banged the first pitch he saw, a 95.4-mph sinker from Reds righty Luis Castillo, off the Great American Ball Park's right-field foul pole for a three-run homer. The rocket had an exit velocity of 106.4 mph and capped a six-run opening frame in the Cards' 11-6 win.

The switch-hitting outfielder went 1-for-3. He homered three times while tallying seven doubles and a triple over 35 games for St. Louis last year and homered twice over 17 Grapefruit League games this spring.

More notable performances from top prospects on Thursday:

Cristian Pache, OF, ATL (MLB No. 12)
A defensive whiz who struggled offensively throughout Spring Training, Pache looped a seventh-inning double down the left-field line off Philadelphia's Aaron Nola to collect a knock in the first game of 2021 that counts. He scored on a homer by Pablo Sandoval. The 22-year-old center fielder had a hit in one of two Braves games he played last year, but he was 7-for-38 (.184) over 17 games this spring. He batted .283 with 21 homers, 30 triples and 76 doubles over 428 Minor League games dating to 2016. Gameday »

Randy Arozarena, OF, TB (MLB No. 34)
The sensation of the 2020 postseason would have had to have a special day to pick up roughly where he left off, but he did achieve exit velocities over 100 mph on the first two baseballs he put into play this year, both against the Marlins' Sandy Alcantara. The first (104 mph, scooting through the right side) was good for a single in the opening frame. The second (100.5 mph) was fielded by Jazz Chisholm for an out in the third. Gameday »

Taylor Trammell, OF, SEA (MLB No. 100)
Making his Major League debut, Trammell was placed in the heart of the order and the outfield. The left-handed hitter went 0-for-2 to start the game, but then worked a bases loaded walk and came around to score as part of a six-run eighth inning for the M’s. Trammell then led off the 10th with a walk to kick off a walk-off victory against the Giants. The center fielder also contributed from the grass, nabbing Evan Longoria as he tried to stretch a single into a double. Gameday »

Jonathan India, 2B, CIN
India, who opened camp as something of a long shot to make the Opening Day roster, showed a sense of belonging with a 2-for-4 performance against the Cardinals. The 24-year-old infielder yanked a double into left field against Jack Flaherty in the fourth, then scorched a single off Ryan Helsley with a 109.7-mph exit velocity in the sixth. Gameday »

Kyle Isbel, OF, KC
Isbel has opened his career with a .600 batting average, going 3-for-5 in his Major League debut. The 24-year-old outfielder singled against Rangers pitching in the fourth, fifth and seventh, knocking in a run with his opening hit and another with his third. Isbel was 14-for-42 (.333) with two homers and three doubles over 23 spring games. Gameday »

Carlos Hernández, RHP, KC
It was a mere 50 degrees for first pitch at Kauffman Stadium, but Hernández brought plenty of heat when he entered in the third inning. In the midst of a slugfest, the 24-year-old righty held the Rangers to a couple runs on three hits and a walk over three innings, striking out five and repeatedly lighting up the radar gun. Hernandez topped out at 100.4 mph, threw another pitch 100 mph and hit between 98 and 100 with 13 deliveries. He threw 31 of 44 pitches for strikes. Gameday »

Julian Merryweather, RHP, TOR
Merryweather put on just about the best Opening Day performance imaginable for the 29-year-old righty. Getting the ball with a one-run lead in the bottom of the 10th, he fanned three Yankees in succession, setting down Aaron Hicks, Giancarlo Stanton and Gleyber Torres on a total of 11 pitches -- only one ball. His final pitch was his fastest, at 99.1 mph. Gameday »

Jake Fraley, OF, SEA
Like his teammate, Trammell, Fraley showed a lot of patience. The Mariners’ No. 25 prospect was hit by a pitch and worked three walks, including a walk-off free pass in the 10th. With this game, Fraley more than doubled his career total, as he worked just two walks in 70 plate appearances across 2019 and 2020. Gameday »