It's no secret that Isaiah Thomas has been extremely bitter about his trade from the Boston Celtics in the summer and the manner in which it happened.

In several interviews since his departure from the franchise, the 28-year-old criticised general manager Danny Ainge and said he has no plans to ever speak to him again.

Now with the Cleveland Cavaliers, the two-time All-Star will be part of a team tasked with overcoming the Celtics in the Eastern Conference to make it to the Finals for the fourth consecutive season.

At the moment, the rivals are in contrasting forms to begin the campaign.

The Cavs have made an underwhelming start as they sit in 11th in the east with a 6-7 record whereas the C's currently lead the pack at 11-2 on the wave of a 10-game winning streak.

IT is fully aware of how his old team are playing and said it's something he expected because of their personnel both on and off the floor.

"I knew they were going to be good. They won 10 in a row, that's definitely a surprise. That's hard to do." Thomas told Joe Vardon of Cleveland.com with regards to the Celtics.

"Like, they've got good players, they've got a great coach. That was going to happen. It's not like they traded me and they were going to be a bad team. They were definitely going to be a good team no matter what. They've got good players on top of having a great coaching staff."

After the gruesome injury to Gordon Hayward, many had already written Boston off and believed their hopes of competing for a championship this year ended in that moment.

But they have responded brilliantly with Isaiah's replacement Kyrie Irving playing a huge role in their success with some special performances.

Head coach Brad Stevens also deserves a lot of credit and is enhancing his reputation as one of the best young coaches in the league.

The early signs would suggest that the Celtics were right to make the trade for Irving and give up Thomas.

The new Cavaliers point guard called the move a "mistake" in a previous interview and thinks people should reserve judgement for when the playoffs start.

"We'll see what happens toward the end of the year and once we get to the playoffs and things like that, but, I knew they were going to be good," Thomas said.

The All-NBA man is making good progress in his recovery from a hip injury and is on course to make a return by January and finally take to the floor for his new team.