But James projected confidence looking ahead to Game 2.
"I've always stayed even-keeled with the postseason," James said after registering his 20th career playoff triple-double with 24 points, 12 assists and 10 rebounds. "I mean, I'm down 0-1 in the first round. I was down 3-1 in the Finals. So I'm the last guy to ask about how you're going to feel the next couple days."
Indeed, James and the Cavs crawled back from a 3-1 deficit against a record-setting Golden State Warriors team in the 2016 NBA Finals to capture the first championship in franchise history.
But that team had more time together and a combination of more top-level talent (such as Kyrie Irving, now with the Boston Celtics) and more playoff-tested role players (such as Richard Jefferson, now with the Denver Nuggets) than this season's.
Game 1, according to James, was a rude awakening for some of his teammates getting their first real taste of competing in the playoffs on a team with a target on its back as a title contender.
"We had some guys in their first time out there playing in this setting, and they definitely ... Like I told you guys, you always ask me, 'Is there anything you can tell them [about the playoffs]?' Listen, experience is the best teacher, and they got it today," James said. "I think everybody is going to be a lot more calm and a lot more precise in what we want to do, too. So it's definitely a feel-out game. We'll see what they're going to do."
Jordan Clarkson, making his playoff debut, was 2-for-6 from the field. Rodney Hood, making his first career playoff start, scored seven points on 3-for-7 shooting, but five of those points came in the fourth quarter with the game already out of hand. Jose Calderon, who has never made it out of the first round before, went 0-for-3. Jeff Green, whose career scoring average of 11 points per game in the playoffs coming into Sunday was already underperforming compared to his career regular-season scoring average of 13.2 points, scored zero points on 0-for-7 shooting.
"I think the intensity," James said when asked where the Cavs tripped. "How much different a regular-season game is compared to a postseason game. It happens that fast. You always hear people say in the regular season, sometimes it's a 'playoff-type atmosphere.' Eh, you can't simulate that. You can't simulate that speed. You can't simulate what's going on out there. So today was definitely a good test for some of our younger guys, and like I said, I think they'll be a lot better, especially in Game 2. And not just them. Even the older guys as well. Some of the guys even with experience, including myself, I can be a lot better as well. So we take it as everybody has to dig deep and not lose two of them on our home floor."
James led all players with 44 minutes played -- none more entertaining than when he was matched up against his old foe, Lance Stephenson.
The Pacers' backup forward made his stamp on the game by scoring 12 points off the bench in 17 minutes and adding five rebounds, but he was also called for a technical foul for striking James in the head after he was whistled for a common foul for body-checking him.
"Listen, it's fun," James said of Stephenson. "He's a competitor. He don't back down from nobody, and I definitely don't as well. So it's going to be a good series."
Indiana coach Nate McMillan acknowledged that he kept Stephenson on somewhat of a short leash.
"He did some good things," McMillan said. "We knew that the eyes were going to be on both he and LeBron. You have to control your emotions out there. You can't be drunk on emotions. I thought we kind of lost it there for a little bit in that second half. We made a substitution, and we was able to get it back. You don't want to take aggressiveness away from your players, but you've got to be smart out there and calm and make good decisions."
Stephenson shrugged off the technical -- "I don't care. They called it. I don't care." -- and volunteered to go at James again as the series continues.
"As long as my teammates have my back, I'll control what I can control," he said. "It's the playoffs. You expect to be pushed."
We'll see just how far the Pacers can push the Cavs if they go up 2-0 after Wednesday's Game 2.
"I get to rest," James said. "I'll take the two days. I need the two days now. I didn't expect to play 44. But I get an opportunity to take the two days, me personally, and I hope the guys do the same thing to try to get their minds and their bodies refocused on what we need to do to win a ballgame."