DALLAS _ This is the difference between really good NBA teams and those fighting just to be mediocre.
The Mavericks _ who admittedly have some traveling to do to get mediocre on the radar _ had the Boston Celtics down by 13 points with just over seven minutes to play Monday night.
Those would be the Celtics who own the NBA's best record and winners of 15 in a row coming into this game.
Within a blink, the visitors stormed back behind Kyrie Irving, found a way to get to overtime and took charge in the extra frame for a 110-102 victory, dishing out a heartbreaking loss to the Mavericks, who fell to 3-15.
Irving was a monster throughout, finishing with 45 points and six assists. He drew the Celtics even at 100 with two buckets after the Mavericks had scored twice to open the overtime.
After two free throws from Harrison Barnes, Irving connected on a jumper and then had Jaylen Brown join in with a midrange jumper and 104-102 Boston lead with 1:39 to go.
Moments later, Irving wheeled on the baseline and flipped a reverse over his shoulder that found the net as he was fouled. He missed the free throw, but when J.J. Barea missed on the other end, the Celtics had control and their 16th consecutive victory.
After starting the game in a trance, failing to move the ball more than one pass on most offensive possessions in the first quarter, the Mavericks figured out Boston's switching, long-armed defense, moved the ball well and outscored the Celtics 55-35 in the second and third quarters combined.
That gave them an eight-point lead that grew to 87-74 with just over 7 minutes remaining.
The Mavericks were surviving despite a huge night by Irving, who didn't miss a shot until the halftime buzzer and was a beast all night.
If the Mavericks wanted to provide Dennis Smith Jr. with the complete how-to kit on what he should aspire to, it dropped in their laps in the first quarter.
Irving, who before the game Rick Carlisle called "second to none" when it comes to creativity with the basketball, gouged the Mavericks for 18 first-quarter points.
In addition to Irving putting on a show, the Celtics also dished out some hard-core defense early on. They came into the game leading the league in field-goal percentage defense (.430) and scoring defense (94.4).
Carlisle equated the Celtics, who start 6-10 Al Horford at center, to the Golden State "death lineup" that features 6-8 Drayond Green at center.
"They got terrific athletes, a level of tenacity that's really exceptional, they play angles well, they're obviously very well coached and they play to their strengths," Carlisle said. "They do a lot of switching, which makes it tougher."
And yet, the Mavericks were handling the Boston defense just fine through three quarters.
When they got a three-point play by Barnes to make it 56-53, they didn't exhale, but mashed on the gas pedal.
They pulled ahead 70-63 and that lead grew to 13 before they needed to hang on for dear life.
