Chuck Liddell got smacked around by his baby mama in court today -- when an L.A. judge ordered the fighter to pay $6,000 per month in child support after Chuck no-showed to the hearing.
Liddell has been going toe-to-toe with his ex Lori Geyer for months -- in an effort to gain custody of their 12-year-old son.
But today in L.A. County Superior Court, the judge came down hard on Liddell -- because in addition to the child support, Liddell was also FINED $2,500 for failing to produce financial documentation requested by the court.
TMZ contacted Liddell's lawyer, who told us Chuck didn't show because "[Lori's] attorney failed to provide notice in an attempt to obtain favorable decision."
But Lori's attorney, Brian Kramer, tells us he has proof that Chuck received notice -- adding, "[Liddell's lawyer] had no valid excuse to boycott these proceedings."