For those who came in late, the Commission slapped Google with a record 4.3-billion-euro ($4.5 billion) fine for running agreements requiring phone manufacturers to pre-install Google Search, the Chrome browser, and the Google Play app store on Android devices, while restricting them from using alternative versions of the Android operating system. EU regulators determined that these conditions stifled competition.

After lower courts largely endorsed the Commission, Google appealed to the Luxembourg-based Court of Justice of the European Union (CJEU), arguing that the penalty unfairly punished the company for its innovation and market success.

Google lawyer Alfonso Lamadrid argued before the court that while the company acknowledges its legal responsibilities, the Commission overreached in its decision-making process.

"Google does not contest or shy away from its responsibility under the law, but the Commission also has a responsibility when it runs investigations when it seeks to reshape markets and second-guess pro-competitive business models, and when it imposes multi-billion-euro fines," Lamadrid told the court.

He further contended that the Commission "failed to discharge its burden and its responsibility and, relying on multiple errors of law, punished Google for its superior merits, attractiveness and innovation."

Lamadrid, however, defended the agreements, stating that "these agreements and conditions did not restrict competition; they fostered it."

The court’s ruling, expected in the coming months, will be final and cannot be appealed.