"I mean, I give [the Golden State Warriors] credit," Tatum said after Boston's 107-97 loss to Golden State in Game 4 at TD Garden on Friday night knotted the series at 2-2. "They're a great team. They're playing well. They got a game plan, things like that.
"But it's on me. I got to be better. I know I'm impacting the game in other ways, but I got to be more efficient, shoot the ball better, finish at the rim better.
"I take accountability for that."
Tatum has not played to the standard he has set for himself in this series. He is shooting 34% from the field, and although he has passed the ball beautifully in Boston's two wins, compiling 22 assists and four turnovers, he has nine assists and 10 turnovers in their two losses.
Tatum, along with the rest of the Celtics, short-circuited in the fourth quarter Friday night, making just two shots over the final seven minutes. That allowed Golden State to close the game with a 21-6 run, flipping the outcome in its favor to even the series.
"We obviously felt like we put ourselves in the position to win the game," said Tatum, who was 1-for-5 in the fourth quarter. "There's a lot of things we wish we would have done differently, especially on the offensive end. I think we just got way too stagnant late in the fourth from everybody."
All of that, however, starts with Tatum, who earned MVP honors in the Eastern Conference finals and is the face of the Celtics franchise. He has been shown as the opposite number of Warriors star Stephen Curry throughout this series, but on the court Curry has been peerless.
That was certainly the case in Game 4, when Curry had 43 points, 10 rebounds and four assists and dominated every second he was on the court. Tatum's night, meanwhile, was emblematic of Boston's poor decision-making for much of the game. He had five turnovers and was a big part of the team's stagnant offense down the stretch.
Asked if he is putting too much pressure on himself, Tatum said no and that he just has to be better.
"I think that's just as simple as it is," he said. "I just got to be better. I know I can be better, so it's not like I, myself or my team is asking me to do something I'm not capable of. They know the level and I know the level that I can play at.
"It's kind of on me to do that more often than not just to help my team in the best way that I can. It's not too much pressure at all. It's kind of like my job."
When asked what he has seen from Tatum so far in this series, Celtics coach Ime Udoka pointed to his hunting for fouls instead of trying to finish through contact.
"At times he's looking for fouls," Udoka said. "They are a team that loads up in certain games. He's finding the outlets. Shooting over two, three guys. That's the balance of being aggressive and picking your spots and doing what he's done in previous games, which is kicked it out and got wide-open looks.
"That's the ongoing theme, so to speak. Him getting to the basket, being a scorer as well as a playmaker. They do a good job with their rotations. Sometimes hunting fouls instead of going to finish. I've seen that in a few games so far."
Moving forward, what the Celtics need to see is the Tatum who showed up time and time again in big spots earlier in these playoffs, such as his 46-point effort in Milwaukee in Game 6 of the Eastern Conference semifinals to stave off elimination against Giannis Antetokounmpo and the defending champion Bucks.
A similar performance in Game 5 in San Francisco on Monday night could allow Boston a chance to close this series out back in Boston next Thursday in Game 6.
Tatum said he remains confident he and the Celtics can bounce back.
"We don't do this s--- on purpose," Tatum said. "I promise you we don't. We're trying as hard as we can. There's certain things we got to clean up. Obviously turnovers, movement on the offensive end. Would we have liked to have won today and be up 3-1? That would have been best-case scenario.
"But it's the Finals. The art of competition, they came here feeling like they had to win. It wasn't easy. I think that's kind of the beauty of it, that it's not going to be easy. It shouldn't be.
"We know we both want it, and we got to go take it."