The U.S-EU deal covers products including U.S. lobsters and EU glassware and ceramics valued at $200 million of annual trade, a tiny fraction of the 616 billion euros (568.32 billion pounds)of transatlantic goods trade in 2019.
Dombrovskis, who is set to take charge of trade at the EU executive, said the deal, the first tariff reductions of this type in more than two decades, was small in economic terms, but big politically.
However, he cautioned against expecting further such small deals, partly because of differences of views about whether to include agriculture as part of trade talks.
"Currently there are no new mini-deals imminent," he told a seminar organised by BusinessEurope. "We had been very clear that our mandate only covers industrial goods, whereas the U.S. wants to include agriculture."
Fish products are considered industrial goods.
However, Dombrovskis did say he hoped the deal would serve as a "springboard for greater things".
The commissioner said the European Union particularly wanted to resolve a long-running dispute over civil aircraft subsidies.
The United States has already received authorisation from the World Trade Organization to impose tariffs on $7.5 billion of EU goods over subsidies given to European planemaker Airbus.
However, the EU is expected to learn within weeks from the WTO the level of retaliatory tariffs it can impose over subsidies given to Boeing.
"Instead of imposing tariffs, I want to find solutions," Dombrovskis said, adding he had already spoken to U.S. Trade Representative Robert Lighthizer.
(Reporting by Philip Blenkinsop; editing by Carmel Crimmins)