The $1.05 billion a jury awarded Apple (NASDAQ: AAPL) last August for damages resulting from Samsung’s patent infringement just got a lot smaller.

In what can only be read as a major defeat for Apple, U.S. District Judge Lucy Koh March 1 threw out the damages award against part of the Samsung mobile devices contested in the case, effectively paring, at least for now, Apple’s victory spoils by some $450 million to about $600 million.

Koh then ordered a retrial on 14 Samsung devices in question--Galaxy Prevail, Gem, Indulge, Infuse 4G, Galaxy SII AT&T, Captivate, Continuum, Droid Charge, Epic 4G, Exhibit 4G, Galaxy Tab, Nexus S 4G, Replenish and Transform--or the $450 million part.

Samsung enthusiasts shouldn’t be too emboldened by Koh’s ruling: The patent infringement ruling for the 14 devices stands, it’s only the associated damages that now are back in play.

In her ruling, Koh wrote that even though she agrees with Apple’s argument that the jury’s award should prevail in this case, she believes the evidence as pertains to the 14 products at issue does not support the award.

“Samsung argues that it is apparent, from the damages amount the jury returned, that some of the awards rested on impermissible legal theories. Apple argues that the Court should not consider how the jury arrived at its award, but should rather only look at the final number, and consider whether that number could have been supported by the evidence in the record as a whole. Apple is correct that courts are generally required to give great deference to jury awards, and to uphold them where they are supportable by the evidence in the record,” Koh wrote in her ruling.

And then she ordered a new trial to determine the proper damages award. “Because the Court has identified an impermissible legal theory on which the jury based its award, and cannot reasonably calculate the amount of excess while effectuating the intent of the jury, the Court hereby orders a new trial on damages. …”

The “impermissible legal theory” to which Koh refers is her determination that the jury’s award to Apple relied far too heavily on estimates from Apple expert Terry Musika. She also threw out Apple’s request for additional damages, deferring any discussion of suitable pre-judgment interest or supplemental damages until all appeals in the case are exhausted.

Koh’s ruling served Apple with a double-whammy for the day, as its stock, which continues to slide, hit a 57-week low on Friday, slipping to less than $430 for the first time since Jan. 24, 2012, as reported here.