The Cavs were outscored 11-0 at the end and committed six turnovers in the 4th quarter. With time running out the Spurs went to a full-court press that caught the Cavs by surprise and threw them off their game. The Spurs also did a good job of attacking the rim immediately to draw fouls and score points with the clock stopped.
The Cavs did a horrible job of reacting to the Spurs final push, although it should have been expected. When you have to make up a lot of points in a short time you have to either attack the rim immediately or put up a quick 3. You can't spend 20 seconds setting up a 2-point jumper. And then you need to full court press and get a turnover or two, which the Spurs did.
The Cavs need to get better at this. They got lucky this time when the Spurs were down by 2 with 40 seconds left and Wemby got the ball in the lane guarded by LeVert. It was an easy basket, but Wemby caught a glimpse of Sochan under the basket and shoveled him the ball. Allen was all over him along with Okoro (I think) so he decided to pass it out for a 3-point attempt, but the pass was off target and went out of bounds.