His high school coach didn’t see it. “I just wanted him to be a good Husky,” said Lindsay Bemis, Isaiah Thomas’ coach at Curtis High in Tacoma, Washington.

His college coach didn’t see it, either.

“For him to be in the conversation for MVP of the whole NBA, I have to admit I didn’t predict this,” said University of Washington Coach Lorenzo Romar.

Not even former Boston Celtic Evan Turner, an eyewitness to Thomas’ ascension, saw it.

“He told me this summer that there was going to be a jump in his game,” said Turner, who spent two years in Boston before signing with the Portland Trail Blazers in July. “And I was like, ‘You’re an All-Star, where the hell are you gonna go from here?’ ”

Oh, Evan, you had no idea.

The NBA has been generating a lot of “-bles” lately. Russell Westbrook is incredible, LeBron James is unstoppable and Stephen Curry is unbelievable. Kevin Durant is unguardable, James Harden is remarkable, and as a two-way player, Kawhi Leonard is incomparable.

But what about the 28-year-old Thomas? What about a 5-foot-9 point guard who is leading the NBA in fourth-quarter scoring while catapulting the Celtics to a 35-19 record? I’ll tell you what he is – impossible.

There have been successful NBA players under 6 feet – Calvin Murphy and Michael Adams to name two – but none has had a season as impressive as Thomas.

His 29.9 points per game are 3.4 more than Adams ever averaged and 4.3 points more than Murphy ever did, and those guys played at a far more frenetic pace.

For example, if you look at the points that trio scored per 100 possessions in those respective years, Thomas is at 43.2 compared to Murphy’s 31.8 and Adams’ 31.5. And while that stat may sound like it’s coming from the mayor of Nerd City, the point is Isaiah’s season is unprecedented for anyone his size.

But forget about comparing Thomas to his diminutive predecessors for a minute. That would be like comparing Dennis Eckersley to other side-armers or Eminem to other white rappers. Isaiah isn’t just one of the best “for his size” – he’s one of the best period.

Only Westbrook (30.9) is averaging more points per game this season than Thomas, and the Thunder star hasn’t shot nearly as efficiently.

Thomas has scored at least 20 points in 38 straight games – two shy of John Havlicek’s Celtics record.

The most striking stat, though, is the 10.7 points Thomas is scoring per fourth quarter this year, which is not only the most in Celtics history, but the most since the NBA started tracking that stat 20 years ago. So what happens in that final period?

There are two ways to answer that question. The first is Thomas’ way.

“I’m more aggressive to score and make plays than I am in the first three quarters, because my teammates want me to be,” Thomas said. “Coach (Brad Stevens) puts me in a position to be more aggressive, and those guys look for me to make plays.”

The second way is like this: When the fourth quarter begins, Thomas remembers every slight he’s ever endured – such as being the 60th pick in the 2011 NBA draft – and makes every doubter see the error of his ways.

One minute he’ll launch a step-back 3-pointer, the next he’ll blow by his defender and weave through the trees, and the next he’ll earn a trip to the free-throw line, where he is shooting a league-high 91.8 percent this season.

Thomas’ spurts don’t have the theatrics of a Curry 3-point barrage, but because Thomas can score in such a variety of ways, he’s more dependable in the final minutes.

Thursday night’s performance in Portland was a prototypical example, as Thomas scored 15 of his game-high 35 points in the fourth quarter to help Boston complete a 17-point comeback and down the Blazers. Then again, with family and friends in attendance, he likely played with a little more incentive.

You see, there may no be greater motivation for Thomas than doing Tacoma proud. He sports a “253” tattoo on his back with the words “Tac-town, born and raised” inked underneath. Friday, he drove from Portland to Tacoma to open “Isaiah Thomas Court” at the Al Davies Boys & Girls Club, which featured the Tacoma skyline painted onto the floor.

He choked up during his speech.

“Tacoma made me who I am. It’s everything to me,” Thomas said. “Every time I step on the floor, I’m representing that city.”

The primary message Thomas gave during Friday’s gym opening was that there aren’t any limits on achievement. Nike posters featuring Thomas with the words “Pick me last again” were displayed all over the walls. Nobody else may have predicted that he’d reach this level, but he was sure he would.

Seattle University Coach Cameron Dollar, who recruited Thomas to the University of Washington and coached him for a year, remembers the day Isaiah signed a four-year, $27 million contract with Phoenix in 2014. He was officially set for life, so Dollar sent a congratulatory text.

“He texted back saying, ‘Coach, I’m just getting started,'” Dollar said. “It wasn’t bragging. It was just showing his mindset. He’s working to be the best player ever.”