Maryland’s James Padget, left, goes up for a shot against Mike Glover during Iona’s 89-63 victory in the fifth-place game of Puerto Rico Tip-Off in San Juan. The Terrapins committed 26 turnovers which led to 32 points for the Gaels. (Ricardo Arduengo/Associated Press)

An error-plagued, undisciplined second half that resulted in an 89-63 loss to Iona on Sunday left Maryland basketball Coach Mark Turgeon questioning his players’ toughness in the face of adversity, their ability to follow instructions and their fundamental desire to excel.

The defeat in the fifth-place game of the Puerto Rico Tip-off dropped Maryland to 2-2, obliterated any good feeling from the Terrapins’ come-from-behind victory over Colorado on Friday and baffled Turgeon, who coached despite ailing with kidney stones.

“This is the biggest challenge I’ve ever had in coaching; it’s not even close,” said Turgeon, who turned around struggling teams at Jacksonville State and Wichita State and led Texas A&M to four consecutive NCAA tournaments before succeeding Maryland’s Gary Williams in May.

“I can’t make it any easier on these guys,” Turgeon said, with senior Sean Mosley, who led the team with 21 points, sitting beside him. “The lack of commitment to running the plays the right way is mind-boggling. I’ve never seen anything like it.”

Turgeon cited an offensive play that the Terps ran properly 10 times on Friday against Colorado. According to Turgeon, he called the same play three times in the second half against Iona, and it was botched each time.

That was hardly the only thing that aggravated the coach, who spoke with players in the locker room for an extended time following the defeat, enumerating the myriad ways in which they had performed poorly.

Maryland turned the ball over 26 times, and the gaffes translated to 32 points for Iona (2-1) — more than one-third of the Gaels’ scoring effort.

Beaten on fast breaks by Iona’s speedsters throughout, Maryland appeared to give up on defense down the stretch, surrendering 23 points in the last seven minutes.

And the Terps dished out just nine assists to those 26 turnovers, while Iona finished with 22 assists to 10 turnovers. Iona senior point guard Scott Machado accounted for 15 of the Gaels’ assists, firing well-timed, pinpoint passes to whoever had scoring position.

Maryland sophomore guard Terrell Stoglin, who scored a career-high 32 points against Colorado, finished with 17 points on 7-of-17 shooting while accounting for just one assist and four turnovers.

The loss wasn’t simply a matter of poor shooting. It had more to do with a breakdown of teamwork, heart and hustle once Iona got the upper hand.

Said Mosley: “We didn’t execute any offensive plays in the second half. When things go south, guys on the team put their head down. . . . We’ve got to get tougher.”

Turgeon had warned that Iona would test Maryland’s transition defense and ball-handling. The Gaels did, determined from the outset, according to guard Lamont Jones (22 points), to make a statement against an ACC team with their speed and pressure defense.

Maryland had 10 turnovers in the first 10 minutes. Freshman point guard Nick Faust picked up three fouls in the first 12 minutes, and Mychal Parker and Mosley also drew multiple fouls quickly, forcing walk-on Jonathan Thomas into action earlier than planned.

Trailing 35-25, Maryland went on a 9-2 run to close the first half down by three, 37-34.

But less than five minutes into the second half, Maryland trailed by 14. And Turgeon, whose foot-stomping, arm-flailing and barked instructions appeared to make little difference, screamed at his players during the timeout that followed.

Maryland pulled to 56-49 at roughly the 10-minute mark. But a dreadful sequence followed in which a flurry of Maryland miscues led to a 12-0 Iona run. James Padgett made his way to the foul line but missed both attempts. Faust passed the ball when Mosley wasn’t looking. Parker was stripped. And each flub led to a fast-break basket for Iona.

“We were confused,” Turgeon said. “We were selfish, I don’t know how many times we can ask these guys to run back [on defense], and they still don’t do it the way they need to do it.

“It was a bad day.”