P.J. Washington urged the Dallas Mavericks to "stay connected and together" following defeat to the Boston Celtics in their NBA Finals opener. 

The Mavs' first championship series since they were crowned champions in 2011 began with a 107-89 loss against the top seeds of this postseason at TD Garden.

It was Dallas' lowest scoring total during the playoffs, while their tally of just nine assists was the fewest in any match this term as they struggled against a strong Boston defense.

"We just have to stay connected [and] stay together," said P.J. Washington. "We are a great team. They are a great team at the end of the day. We're all right. It's only one game. We'll be better for Game 2."

"The ball has got to move a little bit more," added Kyrie Irving, whose 31.6 per cent shooting from the floor was his lowest in 14 career Finals games.

"That starts with me just being able to push the pace, get us some easy opportunities, and just adjust to what they are throwing at us.

"It's a fun series. It was fun going into the game. It's still going to be fun. But there's going to be a level of chess that still has to be played."

Mavs coach Jason Kidd also issued a rallying cry to his players, who he insisted must not be held back by the occasion.

"Give the Celtics credit," he said. "They did a great job defending, making it tough on us.

"I think this is the best team in the NBA, and they are good for a reason. They play their style of basketball at a high rate. Nerves or not being in this situation, we can't use that as an excuse. It's just basketball."