Mavs guard Jason Terry pushed Lakers guard Steve Blake in the fourth quarter of a blowout win for L.A. and Barnes intervened, first pushing Terry, then popping off at referee Joey Crawford to earn an ejection and finally shoving Dallas assistant coach Terry Stotts to the floor as he held Barnes back from Crawford.
It was an angry sequence from an angry player who struggled through his first season with the Lakers, derailed by what he called his first major injury when he tore cartilage in his right knee in February and never found his rhythm when he returned.
The defining play for Barnes in the finale of the Lakers' regular-season series with the Mavs this year, a 112-108 overtime win for L.A. on Sunday, was a revelation.
The Lakers led 110-108 with 15 seconds left in overtime when the Mavs set up a pick at the top of the key that freed Terry to drive into the paint with a head full of steam.
Terry was primed to get to the hoop, tie the score and force double OT -- no doubt an anxious moment for the Staples Center workers waiting to turn the arena over for the Los Angeles Kings' NHL playoff game later that night -- before Barnes swooped in and made him miss the shot.
"I thought [Barnes] was going to try to take a charge or go for a hard foul and he did neither," Terry said. "Give him credit."
While the replay looked like Barnes just went airborne and took a swipe at the ball, it was a calculated defensive possession by the 6-foot-7, 226-pound forward dealing with Dallas' speedy 6-2, 180-pound guard.
"[Terry] always likes to put his leg out and kick you and then go a little higher and get the and-1," Barnes said, "so I kind of moved inside and just tried to block it and he just ran out of real estate."
Barnes had another key defensive play late in the fourth quarter, this time guarding the 7-foot, 245-pound Dirk Nowitzki on the block with the Lakers leading 97-96 with 1:31 left.
As precise as he was when he made sure he didn't make contact with Terry, he was purposefully all over Nowitzki, banging with him in the post.
"I just tried not to give him any angles and kept poking at the ball and made him shoot a deep turnaround shot," Barnes said.
While Nowitzki's turnaround shot didn't fall, Barnes' turnaround season is in full swing.
Barnes finished with 11 points, 11 rebounds and eight assists off the bench Sunday. He shot 4-for-7 overall and 2-for-3 on 3-pointers, marking the fourth straight game that he's shot 50 percent or better from the field. His uptick in production is arriving at the time the Lakers need it most, with Kobe Bryant out of the lineup because of a left shin injury.
Barnes scored his most points as a Laker on Friday in a win over the Nuggets, putting up 24 points and 10 rebounds. The performance prompted Metta World Peace to call Barnes the one player leading the team the most at this point in the season.
"Out of all the players, Matt's been consistently doing the championship necessities in order to win," World Peace said. "We must get to his level. … Matt Barnes is on a whole other level right now. He's very fired up. You can see the red in his eyes. We all must get on that level."
"As hard as he works, good things are bound to happen because he's long and he's athletic and he's worked extremely hard on his shot," Brown said. "He's a factor on both ends of the floor now. He's a guy who reminds me, sort of, of a guy like Bruce Bowen."
Barnes would probably enjoy the comparison because of Bowen's championship rings, but not his bowties. Barnes has his own clothing label and employs a personal stylist. Barnes, who becomes a free agent this summer, could be in position to go on a shopping spree in Milan if he keeps up this level of play and secures a multiyear deal from either the Lakers or another suitor.
"I'm just more focused on the opportunity we have here to win a championship," Barnes told ESPNLosAngeles.com when asked about the impending free agency. "Obviously you know if you play well in the playoffs, good things happen to you. So, that's really my main focus."
The win gave the Lakers a 4-0 season sweep of the Mavericks. It also solidified the possibility of the Lakers, currently seeded third with a 1½ game lead over the No. 4 Los Angeles Clippers, meeting the Mavs, seeded sixth, in the first round.
"We still have that bitter taste in our mouth," Barnes said. "We'll definitely take a sweep in the playoffs over a sweep in the regular season, so we know these games don't really mean too much because if we get a chance to see them in the playoffs, that's when it matters."
There was a fire in his eyes, the kind World Peace spoke about. There's a good kind of anger that comes with Matt Barnes. He may have finally figured out how to harness it.