He's actually correct, until proven otherwise... the qualifier is "in the series". This is a matchup league and in this particular series, if it plays out as dictated last night, then it would be hard to argue against his statement.
In the Chicago series, Gerald Green was better than Jae Crowder... the statement wasn't anything emotional just a fact if we can't properly matchup. In Game 7 at Washington, KO was better than Horford. A series is 4 - 7 games long, to say "best in the series" is not an overall indication of ability.
Because truth be told... I'm missing Sully right now.