Middlesbrough boss Tony Mowbray believes Birmingham's struggles this season highlight the strength of the Championship.
Lee Clark's men currently lie in 14th place in the table, only seven points clear of the relegation zone having dropped out of the Premier League two seasons ago.
Mowbray told the club's official website: "Birmingham have had an up and down season.
"They're a big city club not long out of the Premier League, and I'm sure their supporters have high expectations.
"But they are not managing to achieve them at this moment in what is a very tough league."
Saints were charged on Tuesday for the unsavoury scenes that followed referee Mark Clattenburg's decision to award a penalty for a Luke Shaw foul on Grant Holt.
Artur Boruc kept out Holt's subsequent spot-kick but Saints' players continued to protest after the 0-0 draw and were joined on the pitch by manager Mauricio Pochettino.
While admitting responsibility, it is understood Southampton highlighted to the FA that such behaviour is not a regular occurrence and that it was the first time they had faced such a charge.
Southampton also pointed to the circumstances surrounding what they felt was an unjust penalty award by referee Clattenburg.
An FA statement read: "The FA has today fined Southampton ?20,000 after they admitted a charge of failing to control their players.
"The incident occurred following the awarding of a penalty to Norwich during the match at Carrow Road on Saturday 9 March."