WALTHAM — Saturday night’s loss to the lowly Washington Wizards was the latest bad loss in a season filled with plenty of wins, according to Doc Rivers. The Celtics coach was asked to explain how his team could lose to a team like the Wizards, which came in with just 13 wins.

“Obviously, if you look at the whole season, it’s been a terrific season so far,” Rivers said following Monday’s practice. “But in that terrific season, we’ve had some bad losses, too. And I tell our guys that. Some of the teams that have beaten us are under .500 and those are tough losses for a team that shouldn’t lose those games. Moral lessons learned and we’ve just got to keep teaching them.”

The Celtics have lost 10 games and one of those losses came to the Cavaliers, one night after the C’s beat Miami in the season-opener. Cleveland comes to TD Garden on Tuesday having lost 16 straight and Rivers said he’s not taking them lightly, and doesn’t expect his players to, either.

“Cleveland beat us once already this year,” Rivers said. “For us, I rarely worry about the opponent, I worry about ourselves. When we play right, I think it gives us an excellent chance to win games. And when we don’t anyone can beat us and that’s been proven this year.”