FAYETTEVILLE — Arkansas pitcher Barrett Astin had an impressive streak entering Friday’s series opener against LSU. The junior hadn’t allowed a home run in nearly 100 innings, dating back to his freshman season with the Razorbacks.

That streak was broken in the fifth inning on Friday night.

It led No. 3 LSU to a win in the first game of the weekend series.

Designated hitter Sean McMullen’s three-run home run pushed the Tigers to a 6-2 win in front of an announced crowd of 8,378 in Baum Stadium. The big blast was the first Astin had allowed in 104 1/3 innings and — despite a seventh-inning home run by Arkansas first baseman Eric Fisher — proved enough for LSU’s 15th straight win.

“Any time is a good time to hit a home run. But that was special for sure,” McMullen said. “As soon as I hit it, I knew it was going (out of the park).”

The home run also helped LSU (33-2, 12-1 in Southeastern Conference) widen its SEC West lead over Arkansas (24-11, 8-5). The Razorbacks will try to pull closer when the team’s meet at 6:05 tonight. Ryne Stanek (3-2, 1.90 ERA) will start for the Razorbacks, while LSU will send Ryan Eades (7-0, 1.30 ERA) to the mound.

McMullen’s big hit, which cleared the LSU bullpen, was his first with the Tigers and broke open a game that began as a pitching duel between Astin and LSU starter Aaron Nola (6-0). Arkansas coach Dave Van Horn said Astin left a fastball out over the plate and McMullen made him pay for it with the deep drive.

The Tigers punched in two more runs off Astin (2-2) in the sixth inning after two batters reached on a fielding error by Brian Anderson and a hit batter. Both runners scored when LSU’s nine-hole hitter — catcher Ty Ross — slapped a single up the middle to widen the Tigers’ lead to 5-0 lead. It also ended Astin’s night after allowing five runs (three earned) on seven hits through 5 2/3 innings.

“I missed some first-pitch strikes a lot,” Astin said. “I fell behind on batters. It just comes down to the little things – that’s one of them. Just getting ahead of the hitter so they don’t sit on a fastball. That’s what I did in (the fifth) inning.

“A first-pitch fastball. (McMullen) sat on it, and hit it a mile.”

But it wasn’t the only reason Arkansas lost. The Tigers — who Van Horn described as a complete team earlier this week — showed why with a strong all-around performance Friday. It included a complete game from their staff ace and scores of big plays from a defense that leads the SEC in fielding percentage.

Nola was especially dominant, allowing four hits with 10 strikeouts. He retired 11 straight to start the game before Tyler Spoon singled with two outs in the fourth.

Nola’s only trouble came in the seventh inning, when Anderson hit a deep fly ball that looked like it was clearing the park. Left fielder Raph Rhymes saved a run, though, extending his glove over the wall to make an impressive catch.

“This is the best defensive team I’ve ever seen in college, not even one I’ve coached – ever,” LSU coach Paul Mainieri said. “It's not just fielding percentage, but we make exceptional plays. Even Raph, who has worked so much on his outfield play.”

Arkansas’ didn’t stay scoreless much longer, though. Nola walked Dominic Ficociello with two outs. Then Fisher hit a first-pitch home run over the right field wall.

“His first two at-bats he did a good job of spotting his fastball away,” said Fisher, who hit his first home run since opening day. “I knew coming into that third at bat I can’t miss my pitch and he threw it over the plate first pitch and I jumped on it.”

Nola did settle down after a mound visit, got out of the seventh inning and Arkansas never threatened again. His 10 strikeouts were one off his career high of 11.

LSU gave him a little more support with a run in the ninth after Arkansas committed three errors. The Razorbacks finished with four in the game and now have committed an SEC-high 62 this season. It includes 16 errors in the past four games.

“We made three errors in one inning and it only cost us one run,” said Van Horn, whose team has now allowed 33 unearned runs in 35 games. “I think three of the six runs were unearned, which obviously took us out of the game.”

The Tigers, meanwhile, sealed the win with big plays in the bottom of the ninth.

Third baseman Christian Ibarra fielded a tough hop on a ground ball to throw out Spoon to start the inning.. Andrew Stevenson then made a diving catch in center field to retire Anderson. Nola got Ficociello to fly out to end the game.

“That’s one game,” said Van Horn, whose team has lost four straight to LSU. “We’ve got to find a way to win (today) to have a chance to win the series.”