Troubling stat shows just how bad Luka Doncic has been on defense in the playoffs

The NBA Finals has been a one-sided affair, as the Boston Celtics are on the verge of sweeping the Dallas Mavericks to capture their 18th championship in franchise history. Joe Mazzulla's team has just been too much for the Mavs, and one telling stat shows us why.

Luka Doncic is a phenomenally gifted offensive player, undoubtedly one of the very best in the NBA. He's put the Mavericks on his back and carried them through a historically strong Western Conference, taking out the Clippers, the top-seeded Thunder, and the Timberwolves along the way.

Luka is nearly averaging a triple-double in the playoffs, though incredibly his stat line of 28.9 points, 9.6 rebounds, and 8.4 assists is slightly below his regular season average of 33.9 / 9.2 / 9.8. Still, he's been outstanding, and his play, along with the help he's gotten from Kyrie Irving, PJ Washington, Dereck Lively and others has been enough to get Dallas to within one series win of its second-ever title and first since 2011.

Dallas has done well to get this far, but the Mavs are an imperfect team. They aren't very deep, and Luka, for all his talent, is an absolute liability on defense. This about sums it up:

In a league that employs James Harden, it's downright alarming that Luka has the three worst defensive performances of the last 10 years, all in this postseason alone. Luckily for the Mavs, their opponents were unable to capitalize on this fact, as the Clippers were without Kawhi Leonard for four of the series' six games, the Thunder didn't have the playoff experience to take advantage, and the Wolves suffered a letdown after shocking the Nuggets in the second round. The Celtics, however, seem perfectly built to exploit Luka's lack of defense, and as a result, they're one win away from a title.

Luka Doncic's defense in the playoffs has been historically awful, and the Celtics are taking full advantage

Boston often has four players on the court who can shoot and handle the ball, meaning Luka has nowhere to hide. Jayson Tatum, Jaylen Brown, Derrick White and Jrue Holiday can all create their own shot, and each one is fully capable of getting in the lane and finishing, which has led to one of the most embarrassing NBA highlight reels in quite some time.

Charles Barkley of Inside the NBA said "To act like Luka's defense is the reason the Mavs are down 3-0, that's total BS," but both the eye test and the stats say the same thing. Have Luka's teammates done enough this Finals? No, they haven't. You don't get swept for one reason, though. Both things can be true, and both Luka's defense and the lack of help from his teammates are why the Mavs are in such an insurmountable hole.

Look no further than the Celtics to understand why defense matters. Each one of Tatum, Brown, White and Holiday, not to mention Kristaps Porzingis and Al Horford, are two-way players that give max effort on the defensive end. They've made Luka earn his points, but Luka can't say the same.

Luka is great, but he's not everyone's cup of tea. He's constantly yelling at the refs, he never seems to be in peak physical shape, and the heliocentric way the Mavs offense runs isn't always the most aesthetically pleasing thing to watch. This all came to a head as he fouled out in Game 3, then blamed the refs afterward.

Luka is only 25, though, and the success he's had in the postseason still dwarfs most of his contemporaries. He's one of the best players in the league and will have plenty more opportunities, but while there's still lots of time for him to figure out what it takes to win a title, it looks like this year, that time is running out. They say that defense wins championships, and Luka's right now just isn't going to cut it.