Entering this weekend’s series against Wichita State, LSU baseball coach Paul Mainieri changed up the top three spots in his order in an attempt to get his offense going.

The early returns were promising as LSU completed a series sweep of the Shockers, especially in Sunday’s 9-2 win at Alex Box Stadium.

Kramer Robertson, Cole Freeman and Antoine Duplantis combined to go 6 for 12 with six runs and five RBIs in the finale. For the series, they batted .514 (19 for 37).

“The plan was just to do it for one day,” Mainieri said. “Then I liked it so much after Friday night, I might as well stick with it another day. After two days, I said, ‘Well, maybe this is the way to go.’ ”

They wasted no time getting to work Sunday.

Robertson, who entered the series in a mini-slump with just one hit in his previous 15 at-bats, led off LSU’s first inning with a single down the line. He finished the weekend 6 for 12 with seven runs.

He was followed by Freeman, who yanked a single of his own down the left-field line on a hit-and-run play. Freeman finished the weekend 6 for 11 with seven runs.

“I was actually in the box, and I was hoping he was going to give me a hit-and-run, and we were on the same page,” Freeman said. “As an infielder, I don’t like runners moving and then someone taking an aggressive hack. It’s tough to play (defense). If we can do that and put more pressure on them, it’s in our favor. We took care of business today.”

Duplantis looked incredibly comfortable in the No. 3 spot, Robertson’s old place in the order. With two speedy runners in front of him, Duplantis pulled a soft liner down the right-field line to score two runs. In the series, Duplantis went 7 for 13 with six RBIs — four of which came Sunday.

“I thought the whole key to it was Antoine Duplantis driving in so many runs,” Mainieri said. “He hit in the clutch — did a tremendous job for us.”

That two-run lead manufactured by the top three in the order set the tone for another explosive day for LSU (12-4). The Tigers posted multiple runs in the first, third, fourth and fifth innings. The only starter who did not get a hit was Greg Deichmann, whose 11-game hitting streak was snapped.

“Greg didn’t have much of a day, yet we still scored nine runs,” Mainieri said. “I think that tells you a little bit about the balance of our lineup.”

By the time the fifth inning came to a close, LSU led 9-0. That was more than enough for Eric Walker (2-0) and the rest of the pitching staff.

Walker was not as sharp as he was in his previous start against Texas Tech, but he showed a knack for getting out of trouble against the Shockers (8-6).

Wichita State put at least one runner on base against Walker in each of the first five innings. The Shockers had five runners in scoring position in the first three innings, but Walker stranded them all.

“I didn’t have my best stuff," he said. "When runners got on base, I had to bear down and make better pitches.”

He finished with six scoreless innings, striking out three and allowing just three hits to earn his second win.

Sunday was Walker’s final audition to earn a spot in the weekend rotation for LSU’s Southeastern Conference opener against Georgia next week. Mainieri said after Sunday’s performance that Walker would indeed start next Sunday against the Bulldogs.

LSU begins a five-game week against Louisiana College at 6:30 p.m. Tuesday at Alex Box Stadium, a make-up game for the rained-out contest against San Diego this past week. Fans should use tickets to the canceled San Diego contest to attend Tuesday’s game.

Follow Luke Johnson on Twitter, @ByLukeJohnson.