Kevin Costner has won his child support battle with estranged wife Christine Baumgartner.

A judge in Santa Barbara has slashed the child support payments she receives to $63,000 per month, less than half of $129,000 she gets at present and considerably less than the $161,000 she wanted.

The verdict came at the end of a two-day evidentiary hearing in which both parties argued what they believed to be a "reasonable" amount of child support.

Following the judge's decision, Kevin stated that there were "no winners" in the acrimonious legal battle.

The 68-year-old star told Fox News Digital: "You know, when you have a life that long with somebody, there is no winner... and it's this big, crazy thing called life and how it unravels so quickly.

"One minute you feel like you're on top of the world, and then you realise how, you know, how vulnerable you are."

The 'Dances with Wolves' star explained that he and Baumgartner would work out a fair custody arrangement for Cayden, 16, and Hayes, 14, as well as 13-year-old daughter Grace.

Kevin said: "She's an incredible mom. We will figure it out and we'll share. We just got to kind of convalesce right now."

The actor took to the stand for a second time in the last hour of the hearing and explained how he feared that he would have to take on unwanted work if Baumgartner was awarded an "inflated" amount of child support.

He then apologised to his estranged wife, who filed for divorce in May after 18 years of marriage, remarking: "I want to help but the thought of having things inflated to the point I can't do what I want to do...

"Somehow in this unusual world, we didn't make it and for that, I'm sorry."

A trial will take place in November over the prenuptial agreement and Baumgartner's request for spousal support.