The Dallas Mavericks began their offseason on the right foot. They were able to use the 10th pick of the 2023 NBA Draft — the pick they tanked the final games of the 2022-23 season for — to dump Davis Bertans' contract for the low cost of moving down two spots in the draft. In turn, the Mavs selected Dereck Lively II, helping beef up the frontcourt to help address the Luka Doncic-led team's biggest weakness.

Moreover, the Mavs also made use of the trade exception they created in the Bertans deal to absorb Richaun Holmes' contract from the Sacramento Kings, while being rewarded with Olivier Maxence-Prosper, the 24th pick.

Those moves are certainly a masterclass in asset management, as the Mavs made use of their assets to acquire three players who could be of use to the team as soon as next season. Richaun Holmes, in particular, could have a career revival in Dallas, especially when he'll be playing alongside two pick-and-roll maestros in Luka Doncic and Kyrie Irving, who re-signed with the team on a three-year, $126 million deal.

However, if the Mavs were to be serious about contending for a title next season, one would think that more moves could be in store for the team. Signing Seth Curry should do wonders for the team's spacing and Dante Exum could be the team's new Frank Ntilikina, but the Mavs still have one need to fill for them to turn into one of the Western Conference's undisputed best teams.

Here is the biggest need the Mavs must still address after the dust has settled on the first weekend of 2023 NBA free agency.

Mavs' biggest need: A lockdown defender at the point of attack

Team defense has always been a tricky thing to evaluate. In contrast, offensive brilliance is quite easy to point out. There might not be a team sport around other than basketball that could be dominated by one player, the presence of whom guarantees a few wins, a playoff spot, or perhaps even an NBA Finals appearance.

But defense requires five people to be in sync. Given the spacing in today's NBA, a five-man unit that's connected when it comes to making the right rotations and correct reads is necessary for teams to flourish on the defensive end of the floor. So as much as the Mavs try to improve their rim protection, it may not matter in the end if they allow dribble penetration on every possession.

At this point, the Mavs still lack that perimeter defensive anchor — a must for any team trying to win a championship. Just take a look at the rosters of the four teams that made the Conference Finals last season. One common denominator among them is that they boast the services of defenders who make it a point to contain dribble penetration by fighting over screens with their combination of lateral quickness and sublime defensive instincts.

As presently constructed, the Mavs' best perimeter defenders are Reggie Bullock, Josh Green, and Maxi Kleber. Bullock is more of a stifling defender on paper, as advanced stats show that he's not particularly adept on the defensive end. Meanwhile, Green and Kleber, capable defenders as they may be, may not have the ability to remain on the court during high-leverage situations due to their offensive shortcomings.

This was why losing Dorian Finney-Smith, even if trading for Kyrie Irving was too good of an opportunity to pass up on, exposed the Mavs' defense even further. Finney-Smith took on the toughest matchup every night, and he was also a helpful presence on the glass — an aspect of the game Dallas struggled with as they collapsed to end the 2022-23 season.

At the very least, the Mavs will need someone to approximate the impact Finney-Smith had on the team. And despite not having the most enviable treasure chest of draft picks, the Mavs still have a few midsized contracts on the books that they could package to land a 3 and D player.

Tim Hardaway Jr. should be more expendable now that Seth Curry is in town, while JaVale McGee could be lost in the shuffle once more with Richaun Holmes, Dwight Powell, and Maxi Kleber around to fill in the minutes at center.

Perhaps the Mavs could swing a deal for underrated Orlando Magic guard Gary Harris, a 3 and D guard who shot 43 percent from deep last year. Or maybe, against all odds, the Mavs could trade for Toronto Raptors forward OG Anunoby, a player who ranked among the best in most defensive metrics last season.

But one thing's for sure: the Mavs aren't done making moves just yet. Hopefully for Mavs fans, their next move helps them plug their roster's remaining glaring hole.