MILWAUKEE (AP) - Giannis Antetokounmpo's meme-worthy scowl started with a look in the mirror.
The Milwaukee Bucks All-Star was an NBA rookie then, trying to come up with a look he could flash after making a big play. Antetokounmpo thought about the glare his mother would throw his way when he misbehaved as a child. It took about a week to perfect as he struck poses in front of the mirror.
"Now it comes easy. You've just got to put your nose up like this," said Antetokounmpo, wrinkling his face after a recent practice.
It can look so much more intimidating on the court.
As Antetokounmpo's skills reach new heights, so does his confidence as he enters his third career postseason. The Bucks open their first-round series against the Celtics on Sunday in Boston.
"You don't think. It's just second nature. You're just playing now," Antetokounmpo said. "There are points when you're young, you're scared to make the wrong decision late."
This is no longer the gangly, 6-foot-11 forward who would defer during his rookie season in 2013-14. He's a go-to player in the fourth quarter, a do-it-all forward who can ignite the crowd with a rim-rattling dunk or momentum-changing block.
"That's why I think the best players late, I think they have that mindset. They're not scared to take big shots, they're not scared to turn the ball over ... and they're just in general not scared about basketball," he said. "It's something that they've done their whole lives."
It has been quite the journey from awkward 18-year-old rookie to NBA stardom. Former general manager John Hammond, now with the Orlando Magic, scouted Antetokounmpo in the player's native Greece before drafting him in the first round in 2013 with the 15th overall pick.
Some NBA fans questioned the move. Freakish athleticism and a 7-foot-3 wingspan offered the promise of being a tough matchup on both ends of the floor.
Boy, did the gamble pay off .
"I think one thing that is really important is to never underestimate or undervalue the things that he does," Bucks coach Joe Prunty said last month after the forward scored 28 points in a win over the New York Knicks.
Sometimes, it takes Antetokounmpo's absence to make that point stick.
On April 1, Milwaukee led by 18 midway through the fourth quarter in Denver before Antetokounmpo fouled out with 3:43 left. At the time, the Bucks were up by 10 and Antetokounmpo had 18 points and 12 rebounds. They ended up losing in overtime .
Two days later, the Bucks were in another tight game at home against Boston. Playing with a sore right ankle, Antetokounmpo came up clutch after chasing down Jaylen Brown from behind, swatting what looked like an easy layup against the backboard with 53 seconds remaining. The Bucks held on for the win .
"Because my ankle hurt, I wasn't even being 'Giannis Giannis,'" Antetokounmpo recalled with a mischievous grin.
Key positives for Milwaukee from that victory were runs of 11-3 and 16-4 with Antetokounmpo on the bench for rest. In crunch time, Prunty can also put three other proven scorers on the floor with Antetokounmpo in forwards Khris Middleton and Jabari Parker, along with quick point guard Eric Bledsoe.