BOSTON - Certain situations are conjured up as a result of the grueling nature of the NBA schedule that sometimes leave a team running on empty.

That appeared to be the case for the 76ers on Saturday night, but not the Boston Celtics, who avenged their overtime loss at Philadelphia 24 hours earlier, cruising past the Sixers, 92-79, at TD Garden.

Despite being the oldest player on the court, Boston's Kevin Garnett, who will turn 37 before the season is over, looked young and spry against the Sixers, leading the Celtics with 19 points on 7-for-9 shooting.

"The difference between us right now and a team like the Celtics is the Celtics have a mental toughness born through championships and night in and night out being a team that has to play every single night because teams come with their best efforts," Sixers coach Doug Collins said after a game that left both teams with 11-9 records.

"I guarantee that Kevin Garnett's legs weren't the freshest, but his mind was the sharpest," Collins said. "That's what we've got to build. But Boston, they teach you what the next level is about."

Fresh off their win over the Celtics at the Wells Fargo Center, the Sixers responded with the worst half of basketball they've played all season.

They scored just 28 points in the first half - their lowest total in any half this season, and they made just 23.1 percent of their shots (9 of 39).

Down by eight points at the end of the first quarter, the Sixers saw the wheels come off in the second when they shot just 14.3 percent from the floor (3 for 21).

Trailing by 20 points at halftime, the Sixers, who were led by Thaddeus Young's 22 points, rallied in the third quarter, reducing a 21-point lead to 65-57 with a 13-0 run of their own. However, that was as close as they got the rest of the way. The Sixers trailed by double figures the entire four quarter.

Guard Jrue Holiday said that the Sixers were spent after making their push.

"It's exhausting," Holiday said of trying to rally. "Especially on a back-to-back like that. You're down 20 and you get it down to eight and you start feeling good about everything. But you feel deflated because you spend so much energy just getting it back to eight points."

For the Sixers, Holiday (11) and Evan Turner (13) were the only other players to reach double figures in scoring.

Boston got 16 from Jeff Green, 13 from Paul Pierce, and 10 from Brandon Bass.