Sia Wins Battle in Nasty Custody War With Estranged Husband Daniel Bernad

Sia got a huge W in her divorce from her second husband ... his emergency request for full custody of their son was just shot down by a judge.

According to court docs, obtained by TMZ ... a judge ruled most of the facts asserted in the legal docs from Sia's ex Daniel Bernad were old news -- that information was known back in August, when they entered into their temporary physical custody arrangement ... which gave Sia primary custody of their kid and limited monitored visitation for Daniel.

As we reported, Daniel was asking the court for an emergency order granting him sole custody of their 1-year-old, Somersault Wonder Bernad, calling Sia a "serious and immediate danger" to their son over allegations of drug use.

Sia's lawyer -- disso queen Laura Wasser -- pointed out there was no new info that would warrant a change in the custody arrangement, noting Daniel had only monitored visitation because at the time they struck the deal, he was under investigation by the LAPD for child porn. That investigation has since been closed, with no arrest or charges.

Dan vehemently denied any involvement with child porn ... and says he believes Sia may have "planted evidence" in order to restrict his time with their kid.

As for her sobriety, Sia says she's been sober for over 6 months and insists she has repeatedly agreed to drug testing for both her and Dan, claiming it was Dan who refused to get drug-tested on a regular basis.

She says it's true that she suffered from substance abuse 15 years ago, but recovery has been a "cornerstone" of her life.

She says, "Dan's attempt to weaponize my past sobriety journey ... serves no legitimate purpose and is intended only to distort the facts and undermine my credibility."

We broke the story ... the "Unstoppable" singer pulled the plug on their marriage back in March, filing for divorce after only 2 years of marriage.

At the time, Sia listed "irreconcilable differences" as the reason for the split and asked for legal and physical custody of their kid. Sia said she was open to visitation for Daniel.
Daniel's also been fighting Sia over spousal support ... a couple of weeks ago, he asked the judge to order her to pay him more than $250,000 per month.