NBA: Boston Celtics at Philadelphia 76ers

The Celtics’ Jayson Tatum drives against 76ers guard Ben Simmons during the third quarter at Wells Fargo Center on Wednesday.

LIKE most opening games, we really didn’t learn all that much from the Celtics’ opening-night loss in Philadelphia.

But we learned enough to fall back on one of Bill Belichick and Tom Brady’s favorite quotes: “We have a lot of work to do.”

The Patriots usually save those words for all kinds of performances — and it almost becomes annoying when you hear it after a blowout win. But for these Celtics — these new-look Celtics — those words had to ring true after Wednesday night.

If you have taken a minute or so in this space over the summer, you know I have said, on more than one occasion, that Kyrie Irving is a star, one of the league’s true stars and losing him — and the baggage that went with him — was going to have to be dealt with. And that it wouldn’t be easy.

That was certainly on display Wednesday, when, while Irving set an NBA record for a player on a new team with 50 points in his Nets debut (yeah, yeah, he missed the final shot and his new team lost), Kemba Walker was stumbling through a 4-for-18/1-for-6 shooting night. He was a minus-16 and had only two assists in Philly. Hardly an auspicious debut, but he wasn’t the only problem in what was a rather terrible basketball game.

The fear of protecting the rim and of losing the battle of the boards were both on full display. The Sixers are huge. The Celtics are NOT, especially with Al Horford now a Sixer (his new coach called him “maniacally professional”), Marcus Morris in New York and Aron Baynes in Phoenix. The Celtics blocked TWO shots and were out-rebounded 62-41.

The whole thing was sloppy. Another test awaits Friday night when the champion (and Kawhi Leonard-less) Raptors visit TD Garden for the home opener after surviving an overtime battle with the Pelicans that followed banner raising and ring presentation ceremonies Tuesday night.

The Celtics were 7-for-26 from 3-point range (3-for-18 by everyone other than Jayson Tatum). They were also a dreadful 20-for-34 from the foul line (the teams combined to miss 24 fouls shots). And they had no answer for Ben Simmons, who constantly penetrated even though the world knows he doesn’t take outside shots (shooting will be a Philly headache going forward).

Positives from the opener? Gordon Hayward had 25 points and five rebounds and looked very much like the player he was before his horrific leg injury. Tatum, clearly ready to shoot more as he tries to take the next step he didn’t take last year, had 21 points and 10 rebounds but was 8-for-22 from the floor. Marcus Smart had eight of the team’s 18 assists off the bench.

Celtics web contributor Tomek Kordylewski tweeted, “Gordon Hayward had 18 drives last night. Last year he averaged only 5.7 drives per game. For comparison, James Harden averaged NBA-high 19.6 dpg.”

Again, win or lose, one game is too soon. This is, as they say, a work in progress.

You might have noticed Tacko Fall in street clothes on the Boston bench Wednesday night. Turns out the big rookie is in the league’s concussion protocol after hitting his head on a low ceiling at the club’s practice facility. Brad Stevens says Fall is close to a return, but said nothing on how he hopes the kid doesn’t hit his head on a rim anytime soon.

Flash is gone

To say the circumstances surrounding Josh Gordon Wednesday were confusing would be understatement. But the bottom line was, we think, the troubled wide receiver has played his final game with the Patriots.

His New England career? In 17 games, he had 104 targets, 55 catches, four touchdowns, 16.8 yards per catch. A suspension. And what appears to be a rather minor knee injury that landed him on IR, the NFL Network’s Ian Rapoport saying he will be released when healthy, thus eligible to sign with another team.

From Monday Morning Quarterback’s Albert Breer: “Source says Patriots WR Josh Gordon expects to be medically cleared soon, and that his knee injury is “minor.” I was told he ran 22 MPH on the treadmill during a rehab session today. Once he’s cleared, he hopes to be released off of IR and sign with a new team.”

It’s no secret that Brady was upset last year when Gordon disappeared via suspension after Brady invested so much time and effort in him. Now, Gordon’s gone again and Mohamed Sanu is the new toy as the offense looks for some true consistency.

The filing of the Sanu deal — the Pats gave up a second-round draft pick — also confused the situation with tight end Eric Tomlinson, who made his debut Monday night in New Jersey. The team announced Tomlinson’s release but later in the day made it clear he was still on the 53-man.

Cup rematch

The St. Louis Blues, who hoisted the Stanley Cup the last time they visited TD Garden, are in town Saturday night with the Bruins 1-0-2 in their last three games and 6-1-2 on the season.

The B’s took three of a possible four points in their home-and-home with the Maple Leafs, with Tuukka Rask the winner in goal in his 500th career game Tuesday night. Rask is the 28th goalie to play 500 games for one team.

Rask saluted the local fans (who haven’t always been 100 percent in his corner by the way), saying, “It’s one of those milestones you’re only going to hit once, and I wanted to recognize the crowd. They’ve been behind me and the team for so many years.”

New Hampshire’s Zach Sanford had played in four of the Blues’ first nine games heading into Thursday night’s game against the Kings in St. Louis. He had been a scratch for the past four games but an injury to Sammy Blais got him back into the lineup.

“Intensity’s the biggest thing for me with him,” Blues coach Craig Berube said. “When he’s intense and he’s hard on pucks, he has good hands, makes plays. But he’s got to be an intense player and be hard on pucks and be a physical player. That’s his game.”

Turning to baseball, how many out there had the Nationals winning the first two games of the World Series IN Houston? Good for you!

For the record, the Nats have won eight postseason games in a row (after going down 1-2 to the Dodgers in the NLDS) and are 83-40 (.675 winning percentage) since starting the season 19-31.

Finally, the Red Sox announced they have ended their 17-year relationship with stat guru Bill James — and I’m not really sure what that means, if anything.

Mike Shalin covers Boston pro sports for the New Hampshire Union Leader and Sunday News. His email address is shalinmike@yahoo.com. Follow him on Twitter @mscotshay.