For the second time in this series, the Boston Celtics failed to defend their home court against the Philadelphia 76ers. They fell 115-103 and were fortunate to only lose by a 12-point margin.

The Sixers dominated Game 5 from the jump, and they now have a significant 3-2 series lead. They'll have the opportunity to finish the Celtics off in Philly, as Game 6 will be on Thursday night at the Wells Fargo Center.

With their backs against the wall, the C's will have to improve on just about everything from Game 5 in order to stave off elimination. But before we dive into what could be Boston's last game of the season, let's look at where things went wrong in Game 5 with three major takeaways from the crushing defeat.

3. The Celtics couldn't consistently score from anywhere

The Celtics connected on 12 triples in Game 5, which was the exact same amount as the Sixers. Yet, they also missed 26 of them while Philly missed just 18, making their conversion rate from deep a brutal 31.6%.

Unfortunately for the Green Team, their shooting struggles didn't end on the perimeter. In fact, they shot under 50% from inside the arc and missed a lot of good looks throughout the contest.

The most frustrating part of the night though might be Boston's shooting performance from the place where teams can get the most high-quality looks: the free-throw line. The C's went an abysmal 25-of-34 from the charity stripe, which resulted in them leaving plenty of points on the board that could've helped cut into Philly's various leads.

To make matters worse, the Celtics have been a great free-throw shooting team all season. They shot 81.4% from the line during the regular season, the fourth-highest percentage in the entire league.

Meanwhile, the Sixers, who had the highest free-throw percentage in the NBA this year, went a solid 23-of-27 from the line. It might only be a five-point differential, yet Boston could've used all those points when it was on the verge of making the game closer.

2. Boston had no answer for Joel Embiid

Sixers center Joel Embiid raised his first MVP trophy on Friday night, and he played like he deserved every first-place vote in Game 5. The former Kansas Jayhawk put up 33 points, seven rebounds, and four blocks in 37 minutes of play.

The Celtics tried to contain him as much as possible to no avail. Embiid was connecting regularly on his jump shot and was drawing fouls at a high frequency when he drove. Boston threw a lot of different defenders at him, yet none of them could really limit him consistently.

Boston didn't just have trouble with Embiid on defense though. The six-time All-Star was a force in the paint who was making life extremely difficult for the C's. Almost every time the Celtics got to the hoop they seemed to be looking over their shoulder for the lurking big man.

Although Embiid was slowed down by injuries in the first round of the playoffs, he seems fully good to go now. The C's will need to slow him down at all costs if they want a shot at extending the series.

1. Most of the Celtics starters weren't getting it done

Ahead of Game 6, Celtics head coach Joe Mazzulla might have to shake up the starting rotation.

Outside of Boston's duo of Jayson Tatum and Jaylen Brown, the Celtics' starting five combined for only 21 points. Center Al Horford played one of his worst games in recent memory, as he put up zero points and went 0-for-7 from deep.

He's been a huge part of their defense in recent games, however if he's not making shots, someone else might have to fill in for him. Perhaps Mazzulla could give former starter Grant Williams a chance or take more of a defensive angle with Robert Williams III.

The longest-tenured Celtic, Marcus Smart, was also disappointing despite his 14 points. He had two turnovers, went 2-for-7 from the field, and had a rough plus-minus rating of minus-17.

Boston's last starter, Derrick White, had one of his worst games of the series as well. The former San Antonio Spur scored just seven points and missed both of his two attempts from deep.

Overall, Boston's starting five disappointed. And with elimination just one game away, the C's might have to try something new in order to counter Philly. No matter what lineup they bring, the Celtics are in for an uphill battle against a hungry Sixers squad.