Randolph had 25 points and 20 rebounds Monday night as the Grizzlies held the Portland Trail Blazers to nine fourth-quarter points in an 86-73 victory.
"It ain't Chinese algebra," said reserve guard Tony Allen, who was part of the Grizzlies' defensive effort with a pair of steals in the fourth. "If you get stops, and you execute on offense, normally that teams wins."
The win was the third straight for the Grizzlies, and snapped an eight-game winning streak for Portland in Memphis. The Grizzlies hadn't won a home game in the series in almost five years.
And it was a typical night for Randolph, who recorded his fourth 20-20 game with the Grizzlies.
"I just try to be aggressive and hit the glass on both ends and play around the basket," Randolph said.
Wesley Matthews led the Trail Blazers with 18 points, and Andre Miller had 14 points and nine assists. LaMarcus Aldridge scored 13 points for Portland, which lost its second straight after a four-game winning streak.
"We had a bad fourth quarter," Miller said. "The most important quarter, and it killed us. That was the game right there."
Brandon Roy, who entered the game as the Trail Blazers' leading scorer, was ineffective on a bum left knee he tweaked in Sunday's loss at San Antonio. Roy was 3 of 16 from the field and scored seven points.
The fourth quarter was the Blazers' lowest-scoring quarter of the season and Portland put up a season-low total the second straight game.
Portland had only 78 points in Sunday's loss to San Antonio.
"I think the [starting] five, those guys are gassed," Portland coach Nate McMillan said. "I think they have played some heavy minutes. We need the bench to give us a breather. In the fourth quarter, down the stretch, we [are] not able to score late in ball games."
Both teams struggled early from the field, but Memphis got enough of a rhythm to push the lead to 11 early in the second quarter.
Generally, though, it was a half with no flow. A sparse crowd in the FedExForum (announced at 10,467) resulted in little energy in the building.
The biggest excitement came on Mayo's 3-pointer at the horn to give Memphis a 49-42 lead at the break.
Portland erased the halftime advantage, opening the third quarter with a 13-4 run. But back-to-back baskets from Memphis, including another 3-pointer from Mayo, stopped the rally.
Portland allowed Memphis 12 points in the quarter, and the Trail Blazers carried a 64-61 lead into the final period.
But Memphis scored eight unanswered points to open the fourth as they began pushing the ball inside to Randolph. The Grizzlies eventually rebuilt the lead to double digits when Greivis Vasquez hit a 3-pointer as the shot clock expired with just over 7 minutes left. The basket capped a 15-2 run.
The Trail Blazers would end up shooting 21 percent (4 of 19) in the fourth as Memphis pulled away.
"Defense wins games," Gay said. "It's the oldest saying in the book."
Matthews started his first game of the season the last time Portland was in Memphis on Nov. 16, and scored a career-high 30 points. Entering Monday night's game, he was averaging 20.3 points in the 11 games he has started. ... Monday's game was the third in a four-game road trip for Portland. ... Randolph has led Memphis in rebounding in 14 of the last 15 games. ... The Grizzlies' last home win in the series was Dec. 21, 2005. ...Portland C Marcus Camby had 14 rebounds, his 16th game of the season with double-digit rebounds.