OKLAHOMA CITY (AP) — Kevin Durant's work was done early.

After three quarters. Not three overtimes.

Instead of hunting down key shots, he was tracking down a T-shirt from the stands and reveling in the Oklahoma City Thunder's 99-72 blowout of the Memphis Grizzlies on Wednesday night that gave them their first series lead in the Western Conference semifinals.

The Thunder lead 3-2 heading into Game 6 on Friday night in Memphis. They got there with ease considering what happened in a triple-overtime thriller two nights earlier.

"There was no fatigue factor for us. ... I thought our guys came in with focus," Oklahoma City coach Scott Brooks said. "You beat good teams by really executing very well and with good effort, and we did both of them tonight."

After squandering a 16-point lead in the second half and losing Game 3 in overtime, the Thunder blew a 10-point lead in the fourth quarter before winning Game 4 in three overtimes on Monday night.

This time, it was all over well before the final buzzer.

"Going through that kind of molds our character, I think, and brings us closer together," Durant said. "Losing Game 3 the way we did and winning Game 4 the way we did, it kind of showed what type of team we are, what type of courage and heart we have."

Marc Gasol had 16 points to lead Memphis, which didn't have much left after such a draining loss on its home court.

The Grizzlies shot a season-worst 36 percent, matched their lowest point total from the regular season and never put up much of a fight in the second half.

"Shots weren't falling for us but you still have to come with great effort and we didn't bring it at all," guard Mike Conley said. "They outplayed us in every area of the game. I wish I could tell you why. It just wasn't there.

"They hit us and kept hitting us and we didn't fight back."

They were far enough behind that Durant and fellow All-Star Russell Westbrook didn't even have to play in the fourth quarter.

By the end, Durant was wearing one of the same white Thunder T-shirts as the sellout crowd and was standing on the sidelines directing the lineup of reserves that got to play in garbage time.

"It's always better for the home team in these situations, and the team that won the game," Grizzlies coach Lionel Hollins said. "Not only were we physically down, we were probably down a little bit mentally, but I'm not making excuses for our group.

"We didn't play very well. We didn't shoot the ball very well. We missed a ton of layups."

After a classic Game 4, when the Thunder had chances to win at the end of regulation and each of the first two overtimes, Brooks said it was like "three wins in one."

It may have won them at least two.

The Grizzlies were a ragged bunch throughout the game after losing the triple-overtime thriller 133-123 on their home court and can only hope to get re-energized by returning to the FedEx Forum with their season on the line Friday night.

"I don't think we'll have a problem getting up for this one," Conley said. "We got embarrassed tonight."

Zach Randolph, who played 56 minutes in the marathon Game 4, never was effective for Memphis. He finished with nine points and seven rebounds, and even missed four of his first five free throws. He had been averaging 26 points and 14 rebounds in the series.

Gasol, his partner in the potent frontcourt that powered Memphis to a win in Oklahoma City in Game 1, did most of his damage during a 6-minute stretch in the third quarter.

Then the Grizzlies fell hopelessly behind.

Oklahoma City's Nick Collison capped a four-point possession by turning an offensive rebound into a three-point play. When he converted the free throw, it completed a string of seven straight points by the Thunder to bump the lead to 65-46 late in the third quarter.

Memphis didn't stand a chance of a comeback. Too many missed layups. Too many short shots that clanked off the front rim. Too little energy left.

Conley made just 4 of 16 shots, Tony Allen was 4 for 13 and O.J. Mayo 2 for 8 on a dreadful night when nothing was going in.

"We've got our backs against the wall and we've got to bounce back and come out at home swinging," Gasol said. "We have no other chance to lose another one.

"We've got to go right away and win the next game. There's no other choice."

Memphis didn't reach 50 points until there was 2:04 left in the third quarter, and the Thunder quickly squelched any hopes of yet another wild comeback.

Collison had a two-handed dunk, Cook hit a 3-pointer and Nazr Mohammed made a layup during a string of seven straight Oklahoma City points early in the fourth quarter and the lead grew to 27 before both coaches emptied their benches for the final 4 minutes.

Westbrook had 11 points in 25 minutes — half of what he played in Game 4. Mohammed added 10 points and Collison had nine points and 10 rebounds, helping the Thunder to a 50-33 edge on the boards.

Oklahoma City came up empty on its first seven possessions and turned the ball over nine times in the first quarter, but Memphis couldn't take advantage and never led by more than six.

The Grizzlies got just nine points off of the Thunder's 11 turnovers in the first 12 minutes.

"Early on when we had energy, we kept shooting ourselves in the foot by missing layups or turning the ball over in transition or not finishing in transition," Hollins said. "So that was huge."

When the Thunder finally put together 5 straight minutes without a turnover, they stormed ahead with a 15-2 run late in the first half, featuring a 3-pointer by Westbrook and two-handed slams by James Harden and Durant.

Durant thumped his chest after his dunk, with Oklahoma City on its way to a 46-35 halftime lead it would never give up.

NOTES — There have been only six NBA playoff games that went at least three overtimes, and Kendrick Perkins has played in the last two. He was with Boston for a triple-OT game against Chicago in 2009, before Monday night's marathon in Memphis. ... The Thunder came into the game leading all playoff teams in scoring (105.4), free throw percentage (81.0), defensive rebounds (33.8), total rebounds (47.1), blocks (8.2) and personal fouls (26.4). ... After Gasol tipped away a second-quarter jump ball on its way up, referee Monty McCutchen tossed the do-over while Gasol wasn't looking.