Cause for concern: All three 60-win NBA teams suffer Game 1 losses

The Cleveland Cavaliers, Oklahoma City Thunder and Boston Celtics all lost Game 1 in the semifinal round in surprising fashion. It was the first time in NBA history three 60-plus win teams lost their first game in the second round. Should the Cavaliers, Thunder and Celtics worry?

The Cavaliers lost at home to the Indiana Pacers 121-112 on Sunday afternoon. Donovan Mitchell contributed 33 points, five rebounds and four assists. Mitchell led both teams in total shot attempts (30) while doing what he can with the injuries the unit has suffered. 

Darius Garland did not play in Game 1 due to a left big toe sprain he suffered in the regular season. Evan Mobley garnered 20 points and 10 rebounds in the loss, but he endured a sprained left ankle in the affair. De'Andre Hunter suffered a sprained thumb in the loss as well.

Garland is Cleveland's second leading scorer, Mobley is the unit's defensive anchor and Hunter is a solid contributor off the bench. It remains to be seen if either of them will play in Game 2, but they are absolutely going to be needed against an Indiana team that smells blood. 

As for the Celtics, they were up by as many as 20 points in the third quarter against the Knicks at home. Jalen Brunson and OG Anunoby each scored 29 points and came up big late in the game. 

Boston won all four regular season matchups and controlled the bulk of this game against New York, so the loss is somewhat surprising. Furthermore, Boston missed an NBA playoff record 45 three-point attempts. 19 of Boston's 20 shot attempts in the third quarter were from three.

The Knicks sealed the win in overtime. New York stole Game 1 and now has the momentum to potentially dethrone the reigning champions. 

The Thunder lost in dramatic fashion on Monday night against Nikola Jokic and the Nuggets. Jokic garnered 42 points and 22 rebounds in the win. Moreover, Russell Westbrook played his first playoff game against his former team and came up clutch in the waning moments of the game as he assisted Aaron Gordon's game-winning three-point bucket with 2.8 seconds remaining. 

The Thunder were up 113-102 with just over four minutes left in regulation, but the Nuggets kept fighting and closing the gap. 

Is it fair to say that the Thunder's week-long break after having swept Memphis in the first round played a factor? Or perhaps years of playoff battles helped Denver weather the storm? Regardless, it's not the start the Thunder were hoping for.

A Game 1 loss may not be cause for panic, but the Cavs, Celtics and Thunder will be feeling a bit of extra pressure come Game 2.