The Clippers were thankful for the standout performance of Chris Paul, who notched 30 points, 12 assists and three steals to lead his side to victory at the Toyota Center.
"[Our mental fortitude] is big. I think it's what we lacked last year," Barnes told reporters after the game.
"I think it's a big sign of maturity. It comes from more experience. We knew last year that was our weakness; we were mentally weak.
"I think collective focus on being mentally tough has got us a long way this year."
The result sees the Clippers sitting in first position in the Pacific Division with a record of 55-22 for the season.