The win capped the best two-game stretch of holding opponents under 30 percent shooting since 1959.
"We are playing defense much better, helping each other, and rebounding great," Memphis center Darko Milicic said. "We're finishing the game, and that's what's important."
Peja Stojakovic scored 23 points to lead the Hornets, who were without their top three players in Chris Paul, Tyson Chandler and David West. Paul and Chandler were out with injuries, while West was suspended for the game after his flagrant foul against Minnesota's Mike Miller on Sunday.
Antonio Daniels and James Posey each scored 11 points as New Orleans struggled from the field, connecting on only 29.5 percent of its shots. The Grizzlies also held the Toronto Raptors to 29.5 percent in 78-70 win Saturday.
According to the Elias Sports Bureau, it marked the first time in more than 49 years that a team has held consecutive opponents under 30 percent shooting from the field. The last time was Dec. 19-20, 1959, when the then-St. Louis Hawks held Philadelphia to 26.9 percent and Detroit to 29.9 the next night.
Memphis also dominated the boards, outrebounding the Hornets 64-38, including 20 off the offensive glass contributing to 23-8 advantage in second-chance points.
"Anytime you give a team 20 offensive rebounds in a game, you're going to be at a disadvantage," Hornets coach Byron Scott said. "We just did a terrible job on the defensive boards, and they just killed us."
The Hornets weren't the only ones short-handed, though. Memphis was missing second-leading scorer Rudy Gay with a left hip flexor, along with starting rookie forward Darrell Arthur (family reasons) and reserve point guard Kyle Lowry (ankle sprain).
The Grizzlies, who led by 12 in the second half, still held an 11-point lead late in the third. But the Hornets put together a 13-2 run spanning the third and fourth quarters to pull even at 66 on Rasual Butler's 3-pointer.
But Conley and Mayo combined for the next 10 Memphis points allowing the Grizzlies to take the lead it never relinquished.
"We've got to try and limit teams to tough contested shots, and then no rebounds, so we can get out and run," Mayo said.
The Grizzlies opened the second half with an 11-2 run to take its first double-digit lead at 51-41, as the Hornets' shooting dropped under 30 percent.
Stojakovic was doing everything he could to keep the Hornets in the game early in the second half, scoring New Orleans' first seven points in the third period.
"We had to be aggressive. I think we showed the aggressiveness, but we just didn't shoot the ball well," said Stojakovic, who was 7-of-22 from the field. "Another thing is, we allowed a lot of points in the paint."
The play was sloppy at times in the first half and neither team led by more than six points as there were three lead changes and eight ties.
Stojakovic's three free throws with 1.6 seconds left in the half gave him 13 points through two periods, and cut the Grizzlies' halftime lead to 40-39.
The Grizzlies shot 36 percent in the half, while the Hornets were held to 32 percent. Memphis had a 29-18 advantage on the boards, but that was offset by 10 turnovers, leading to 12 points for New Orleans.
"Yes, this was an ugly game," Memphis coach Lionel Hollins said. "It is always beautiful when you execute and win these games. Both teams were a little bit depleted with the offensive people, so we were able to hang on."
The Hornets entered having won seven straight in the series. ... Hornets F-C Sean Marks, coming off a career-high 18 points in Sunday's win over Minnesota, picked up two early fouls and scored just four points. ... Warrick left with 6:36 left in the third after taking a blow that opened a gash above his left eye. He returned early in the fourth quarter with a bandage over the eye covering four stitches. ... Mayo's previous high in rebounds was nine on Nov. 7, 2008, against Golden State. ... Memphis is 4-4 since Hollins took over the Grizzlies on Jan. 25 after Marc Iavaroni was dismissed. ... Hollins said in his postgame comments that Gay wouldn't return until after the All-Star break, and would not participate in the Slam Dunk contest.