"The review by the General Court, in the light of the arguments put forward by Intel, of whether the rebates at issue are capable of restricting competition, involves the examination of factual and economic evidence which it is for that Court to carry out", the European Court of Justice ruling states.
Europe's top judges dealt a rare blow to European Union antitrust regulators on Wednesday by sending their case against US chipmaker Intel Corp back to court for an appeal. Intel had given the rebates to computer manufacturers, presumably to keep them from using AMD chips.
The blow to the European Commission could have implications for other open investigations into pricing by dominant companies including cases against Google and Qualcomm, the telecommunications equipment supplier.
Instead, the Intel case is now likely to drag on for many more years and will fail to bring legal clarity to the closely watched case. It could also force the commission to re-examine its strategy in several ongoing cases.
The Commission and Intel said on Wednesday's they were analysing the verdict and that it was too early to comment.
The General Court had backed the Commission and rejected Intel's initial appeal in its entirety.
It could also make United States tech giants Apple, Facebook, and Google less quick to settle in their European Union disputes by dinting the Commission's invulnerable reputation and by increasing the burden of proof about "restricting competition" on the Commission side.
Intel apparently made payments to Media-Saturn on the condition that it sell only computers containing Intel's x86 CPUs.
The microchip giant then appealed to the General Court, second only to the European Court of Justice, but lost the case in 2014.
Google, which was hit with a 2.42 billion euro fine in June for favouring its own shopping service, is also under fire over its Android smartphone operating system and online search advertising.