Mehta pressed him, for example, on if being dominant in search means that Google's search engine will improve faster than its competitors.
Google's Schmidtlein replied: "Offering a superior product, winning business on the merits is never unlawful."
Google has argued in court filings that the payments at issue are legal revenue-sharing deals and not illegal efforts to exclude rivals.
Since this lawsuit was filed, Google has been hit with other antitrust complaints.
The Justice Department filed a second lawsuit in January accusing the company of abusing its dominance of the digital advertising business.