Philadelphia 76ers star Ben Simmons defended his decision to take a last-gasp shot that missed as the Boston Celtics claimed a 101-98 overtime victory and a 3-0 lead in their Eastern Conference semi-final.

Simmons – coming off the back of a dismal display in game two – finished Saturday's contest with 16 points, eight rebounds and eight assists, but a number of costly errors ultimately proved decisive.

Four turnovers harmed the 76ers bid to claim a first triumph of the series, while his wasteful shot with 19 seconds of overtime remaining gave the Celtics the chance to win.

Rather than taking time off the clock with Philadelphia 98-97 up, Simmons launched a shot that missed and handed possession back to the Celtics.

Simmons had no regrets, though, telling reporters: "I got a shot that I practice a lot, right next to the rim. I had a wide open shot that I make a lot of the time and I missed it

"It was just natural instinct - right next to the rim, it's a shot I take. Every practice, every day, every game, I take one of those ... and I missed it.

"That's the game - you miss shots, you make them. You win and you lose."

A mix-up with Joel Embiid even deeper into overtime capped another frustrating display for Simmons, the confusion allowing the Celtics to intercept and seal the win through Al Horford.

Simmons added: "I have a lot of growing to do. This is the first season I have played, the first time I have played in the playoffs and I'm learning a lot.

"It's a great opportunity for myself and the team. We're all learning together.

"We're very frustrated, but at the same time we've got to look at the next game. Obviously it's going to be hard, but we're up for the challenge."

The 76ers face an almighty challenge if they are to progress in the playoffs, but despite the odds being stacked firmly against them, coach Brett Brown is not giving up hope.

"Teams that are down 3-0 [in the playoffs] have a record of 129-0 [129 defeats and no wins]," he said. "Now think about that. Just think about that number, the number to me, zero, happens more out of spirit than talent. 

"I believe that, if we can maintain our spirit, why couldn't we be the one? And I mean that. I can't see any other way to approach this."