All of the chatter focused on whether or not Marcus Morris could contain LeBron James in the Eastern Conference Finals. Perhaps there should've been more concern over whether the Cleveland Cavaliers could stop Morris. The Boston Celtics forward went off in Game 1 of the series on Sunday afternoon. Morris made it a very special Mother's Day for all the moms in attendance, giving them an afternoon the fans won't soon forget -- all from a player who wasn't even expected to start the game.

Don’t miss on the latest updates Follow the NBA Channel

Morris makes personal history

Just a day before tip-off, nobody even knew Morris was going to draw the start in Game 1. Celtics coach Brad Stevens generally rolled Aron Baynes out to start this postseason.

But Morris was talking a big game about how he was going to be able to stop James on the court all series long. Rather than shy away from the (perhaps misplaced) confidence, his coach gave him an opportunity to back up his boasting.

He largely came through on his promise. James only scored 15 points, his lowest output since a rest-shortened regular season finale. According to ESPN, those numbers looked impressive compared to what the G.O.A.T. accomplished when Morris was tailing him.

Where his presence was really felt, however, was on the offensive end.

Morris had his best game of the postseason thus far, dropping 21 points and ten rebounds while hitting three of four attempts from three-point range. The forward recorded just two double-doubles during the season, his lowest mark in four years. In fact, this was the first double-double in his postseason career.

Needless to say, Celtics fans will be delighted if Stevens continues to start Morris in this series.

Cavs lay an egg

The Celtics definitively won [VIDEO] Sunday's opening salvo. But the Cavaliers lost it too. Cleveland looked flat from the opening tip. Halfway through the first quarter, they already found themselves down by double digits. James faced the largest halftime deficit of his lengthy postseason career. He didn't get much help from his teammates, but his plus/minus of -32 wasn't much to write home about.

Cleveland laid an egg in the opening game of their first-round series against Indiana [VIDEO], too. They managed to take that series to seven games and ultimately win it. So, it's too soon to panic, but the Cavaliers are going to need to kick it into high gear quickly.

They're also going to need to concern themselves with the offense of Marcus Morris.