A jury in the United States has found that the technology giant Samsung stole innovative designs from Apple Corporation to create its own smartphones and computer tablets.
After a year of litigation, which examined some 700 infringement claims, the court in California ordered Samsung to pay more than $1 billion in damages.
The jury rejected claims by Samsung that several of its patents had been breached.
The verdict, which came after less than three days of jury deliberations, could lead to an outright ban on sales of key Samsung products and will likely solidify Apple's dominance of the exploding mobile computing market.
Apple's victory is a big blow to Google, whose Android software powers the Samsung products that were found to infringe on Apple patents.
Google and its hardware partners, including the company's own Motorola unit, could now face further legal hurdles in their effort to compete with Apple.
Samsung lawyers were grimfaced in the quiet but crowded San Jose courtroom as the verdict was read, and the company later put out a statement calling the outcome "a loss for the American consumer".
Apple upended the mobile phone business when it introduced the iPhone in 2007, and shook the industry again in 2010 when it rolled out the iPad.
It has been able to charge premium prices for the iPhone, with profit margins of as much as 58% per phone, for a product consumers regarded as a huge advance in design and usability.
The company's late founder, Steve Jobs, vowed to "go to thermonuclear war" when Google launched Android, according to his biographer, and the company has filed lawsuits around the world in an effort to block what it considers brazen copying of its inventions.
The legal win came one year after Chief Executive Tim Cook assumed the helm of the company.
Shares in Apple, which just this week became the biggest company by market value in history, climbed almost 2% to a record high of $675 in after-hours trade.
The verdict comes as competition in the mobile device industry intensifies, with Google jumping into hardware for the first time with its Nexus 7 tablet, and Microsoft's new touchscreen friendly Windows 8 coming in October, led by its "Surface" tablet.
Apple's victory could present immediate issues for companies that sell Android-based smartphones and tablets, including Google's own Motorola subsidiary, which it acquired last year for $12.5 billion, and HTC of Taiwan.
Amazon, which has made major inroads into the tablet market with its cheaper Kindle Fire, uses a modified version of Android for its Kindle products but has not yet been subject to legal challenge by Apple.