MIAMI -- Kyle Schwarber wasn't happy about his outfield play in the third inning on Thursday, but he said he forgot about it in a few minutes. It showed in the seventh inning, when Schwarber launched a solo homer to help the Cubs beat the Marlins, 8-4, on Opening Day.

Schwarber had worked hard this offseason to slim down, hoping a more svelte physique would help him in the outfield. He still had some trouble on Thursday.

In the bottom of the third inning, Schwarber seemed to have a hard time tracking Derek Dietrich's hit, which ended up as a leadoff triple. Cubs starter Jonathan Lester then walked Starlin Castro and Dietrich scored on a groundout by Justin Bour. The ball had only a 32 percent hit probability according to Statcast™, indicating what should have been a relatively low-damage fly ball.

Brian Anderson then singled to left and Schwarber overran the ball, allowing Anderson to reach third on the hit and error, allowing another run to score.

"The first ball [by Dietrich] just carried," Cubs manager Joe Maddon said. "The second ball [by Anderson], this kind of grass, when it's cross cut it's going to snake. It does snake. The ball's coming right at you and it can make a left turn, and that's what happened to him. When you're playing on that kind of an outfield, you have to be a little bit more cautious as you're coming to the ball.

"He learned a lesson here today," Maddon said. "It could've happened to anybody."

Schwarber may have nightmares about that fine Bermuda grass -- or he might forget it.

"I was over it in two minutes," Schwarber said. "I just had to find a way to move on from that and stay locked in to what's going on in the game.

"I still want to find a way to knock it down or get a glove on it. It is what it is. I was frustrated for about two minutes, because I want to make that play for [Lester]. Obviously, it was frustrating, but you have to be able to move on from it and learn from it. I'm not being mad about it. I felt I moved on from it pretty great and went on with my at-bats."

Schwarber got all of his home run against Miami's Tayron Guerrero, launching the ball 406 feet to right. Maddon thought it was headed to the upper deck but the wind knocked it down. Guerrero had struck out four in a row before the blast.

"I love watching him hit," said Ian Happ, who hit the game's first pitch for a homer, of Schwarber. "He's a special hitter. For him to clip that guy after he struck out four guys in a row was pretty cool."