BOSTON – Karl-Anthony Towns was in a hurry to catch the Timberwolves bus to the airport, and after throwing on his clothes and packing his bags and jewelry, he stopped to talk through some of the team's defensive problems after another substandard showing in a 115-102 loss to the Celtics.

To Towns, the problem is focus, the mental fortitude needed at every moment or else you give your opponent an advantage, something that is happening too often with the Wolves of late.

"I look at basketball more like boxing," said Towns, who has a photo of Muhammad Ali on his Twitter page. "Boxing is such a great sport for me personally to watch, but to train, those guys have to be focused every single second of every single round. One time you're unfocused, you get hit in the jaw and the night is over."

Too often, the Wolves have been getting hit in the jaw, and even though they still have more than half their games remaining, how long will it be before they can't get back up?

It didn't help to have a few holes on the roster. They played without Jeff Teague (left ankle), Derrick Rose (right ankle) and the latest addition to the injury report, Robert Covington (right ankle and knee). The absence of Covington, an All-NBA defensive first-team selection a season ago, no doubt made it tougher to slow the Celtics, who played without All-Star guard Kyrie Irving. Covington is one of the most talkative Wolves on the floor, a defensive floor general for coach Tom Thibodeau. Without him, the same problems the Wolves have had all season were a problem again, things that can be present regardless of absent personnel — such as focus and communication.

That's how the Wolves allowed Gordon Hayward to torch them again, this time for 35 points (he scored 30 in a 118-109 Boston victory on Dec. 1). If you only watched Hayward play against the Wolves, you'd have no idea he was struggling in his return from a fractured ankle. Hayward, who is averaging only 10.3 points per game, has cracked 20 points just twice — and both games came against the Wolves. Towns finished with 28 points, 12 rebounds and seven assists while Andrew Wiggins scored a team-high 31 points.

To Wiggins, the issue is communication.

"That's on us. Just on the players," Wiggins said. "The coaches can coach, but the players who are on the floor, we see what's happening so we have to make the decisions to call what we're doing."

But the Wolves are 38 games into the season, shouldn't they have figured out all these issues by now?

"If it was easy, everybody would do it," forward Anthony Tolliver said. "That's just the sign of a mature, good, well-rounded team is when you do all those things consistently."

Right from the start there were issues, with Thibodeau calling a timeout 64 seconds into the game. The Wolves had one good quarter, the third, when Towns had 20 of the team's 39 points to cut an 18-point halftime deficit to six. But in the fourth, the defense lagged and the Celtics hit them where it hurts.

"We have to make sure every single second we're tremendously focused to our opponent, understanding our game plan," Towns said, continuing his boxing analogy. "If they throw some punches and we get hit, we don't change our game plan as we get hit."

But too often this season, those hits have knocked the Wolves out of balance.