The Cleveland Cavaliers beat the Los Angeles Lakers 120-108 on Thursday night in LeBron James‘ final game against Kobe Bryant, and it seems like his team is taking steps in the right direction after he questioned them publicly.

“I can sit up here and say that we’re a team that’s ready to start the playoffs tomorrow, but we’re not,” James said to ESPN after a 106-103 loss to the Memphis Grizzlies. “We’re still learning. We still have things that happen on the court that just, that shouldn’t happen.”

The Cavs were playing at home and riding a three-game winning streak against Memphis, but they still lost to a team missing starters Mike Conley, Zach Randolph and Marc Gasol. The main thing Cleveland must focus on during the stretch run of the 2015-16 season is defense, because giving up 106 to the Grizzlies and 108 to the Lakers won’t get it done.

If they are lucky enough to make it back to the NBA Finals, then the Golden State Warriors will prove to be much more difficult to defend than Memphis or Los Angeles. And the Cavaliers must bring better effort on the defensive side of the ball to even get to that point of the playoffs.

Kevin Love and Kyrie Irving aren’t exactly known as elite defenders, so if they can at least play mediocre defense while thriving offensively, then the Cavs will have a chance at being champions. If they can’t, though, then Golden State or the San Antonio Spurs will roll over them in the Finals.

Cleveland has a lot going for them right now. They will likely lead the Eastern Conference in wins to end the season, and there isn’t another real contender standing in their path before the championship round. The issue is that they won’t truly be tested until the Finals, and it might be too late by then to learn new habits. They would be wise to improve their defense in the season’s last month, because that could be the difference between success and failure against whichever elite team comes out of the West.