Here's how Tatum did against each Cav defender from NBA.com matchup data.
vs. Allen: 6-for-11 overall, 2-for-6 on 3's, 3-for-4 on foul shots for a total of 17 points in 2:25
vs. Mobley: 5-for-9, 1-for-2 on 3's, 1-for-1 from the line for 12 points in 2:25
vs. Hunter: 1-for-5 for 2 points in 5:42
vs. Okoro: 2-for-5 for 5 points in 0:30
vs. Strus: 3-for-3 for 7 points in 1:05
vs. Wade: 1-for-3 for 4 points in 1:01
vs. Mitchell: 0-for-1 in 1:23
He was 1-for-2 against Garland, 1-for-1 against Merrill, and 2-for-3 against Jerome.
Against bigs (Allen and Mobley) he was 11-for-20 for 29 points in 4:50.
Against guards (DG, DM, Merrill, Jerome, Strus) he was 7-for-10 for 15 points in 4:40.
Against forwards (Hunter, Wade, Okoro) he was 4-for-13 for 11 points in 7:13.
What is most noteworthy is that in the 5:42 that Hunter was guarding Tatum the Celtics scored 10 points. That's 10 freaking points for the whole team in nearly 6 minutes that Hunter was on Tatum. And he missed 4 of his 5 shots.
Dean and Isaac did a solid job, holding him to 3-for-8, but Hunter really shut him down. The Cavs' bigs gave up 29 points in 20 shots and he shot 70% against the guards. He's too quick for the bigs and too big for the littles. In the playoffs Kenny will have to keep Hunter, Wade, and maybe Okoro on him as much as possible. Donovan might be able to guard him as he's strong enough to keep him out of the paint and quick enough to stay in his grill.