Updated

With the game on the line, West Virginia had a huge breakdown on defense.

Josh Gray made a go-ahead layup with 7.4 seconds left and reserve guard Tim Quarterman scored 21 points to help LSU upset the 16th-ranked Mountaineers 74-73 on Thursday night.

"We practice that every day. That's a flat screen. The guard has always taken right and the big takes left," West Virginia coach Bob Huggins said. "The guard jumped to the left. Even with that, I don't get how you shoot a layup from the top of the key and nobody helps."

Jarell Martin had 18 points and 14 rebounds for the Tigers (6-2), who overcame a 14-point deficit in the second half. Keith Hornsby scored 15.

West Virginia (7-1) was off to its best start since opening 11-0 during the 2009-10 Final Four season.

The Mountaineers were led by Juwan Staten's 17 points. Daxter Miles added 13 and Tarik Phillip had 12.

West Virginia led 43-38 at halftime and extended its lead to 14 points in the second half before LSU went on a 15-3 run to pull within three.

Hornsby hit a 3-pointer and two free throws to tie the score at 58.

West Virginia led 66-60 with 5:06 to go. Each team had held a one-point lead until Gray hit the decisive shot.

"I feel like I can get in the lane at will and that's what I did," he said. "The lane opened up and I had a wide-open layup."

West Virginia had one more chance, but Staten missed a jumper with 3 seconds remaining.

Gray finished with seven points, seven assists and eight turnovers.

Ahead by five at halftime, West Virginia opened the second half with nine straight points to take a 52-38 lead with 18:07 to go. Six of the points came off LSU turnovers.

LSU had made just two field goals in the final 6:26 of the first half. But after building its big lead, West Virginia started putting up errant shots.

The Tigers outscored the Mountaineers 15-3 in a span of about seven minutes to cut the margin to three. In the meantime, West Virginia missed seven straight attempts.

Phillip figured prominently in the second half off the bench. His six points increased his team's lead to six and brought fans to their feet with 3:42 remaining.

West Virginia was ahead 71-67 with 1:32 to go, but Martin's tip-in silenced the crowd. That was followed by Hornsby's third 3-pointer in three attempts with 30.7 seconds left to give the Tigers a one-point lead.

Miles' tip-in briefly gave West Virginia a 73-72 edge with 26 seconds to go.

After the Mountaineers gave two fouls, LSU inbounded near halfcourt and Gray delivered.

"We went baseline and we wanted to make sure that we set a screen with a post guy. He had to come off and had to read to see where the help was going to come from. They chose to stay down and the lane opened up," LSU coach Johnny Jones said. "They went four guards and there wasn't a rim protector back there and it made it easier for us to make the layup."

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HOME AND AWAY

It was only the sixth time West Virginia has lost at home in the last 80 games. That covers a span of 12 years. Fifty-five of those home-court wins had come in the previous 58 games. WVU is 40-4 at home under Huggins. ... It was the first game for the Tigers this season on an opponent's campus. Four of their victories have come at home. LSU has also played on a neutral floor three times.

RANKINGS

LSU's previous victory against a ranked opponent on the road also came in Morgantown. The Tigers edged the 13th-ranked Mountaineers 71-68 in overtime on Nov. 26, 2005.

TIP-INS

LSU: Martin fouled out with 26.4 seconds to go, and Quarterman (four fouls) played 30 minutes. Leading scorer Jordan Mickey (17.5 points per game) missed 18 minutes because of three fouls.

West Virginia: The Mountaineers forced 24 turnovers and outscored LSU 25-15 in points off turnovers. Through games of Wednesday night, West Virginia led the nation in steals (97) and steals per game (13.9).

ON THE MARK

The Tigers shot 8 of 15 (53.3 percent) on 3-pointers after entering 29 of 67 (27.1 percent) from long range this season.

NUMBERS GAME

Huggins might have thought he could wear out LSU with a longer bench. The Tigers had played Thursday night, while West Virginia's last game was the previous Saturday. The Mountaineers used 12 players, including Brandon Watkins (illness) and BillyDee Williams (eye injury) for the first time this season. Jones countered with nine players for LSU. Martin played 39 minutes, Hornsby was in for 37 and Gray played 32.

UP NEXT

LSU hosts Sam Houston State on Dec. 13.

West Virginia visits Northern Kentucky on Sunday.