In 2008, Gulbis won his first ATP Tour doubles title at the U.S. Men's Clay Court Championships, teaming with Rainer Schüttler, and in 2010 won his first ATP Tour singles title in the Delray Beach, defeating Ivo Karlović in the final.
Pada tahun 2008, Gulbis memenangkan gelar ganda tur ATP pertamanya di U.S. Men's Clay Court Championships, berpasangan dengan Rainer Schüttler, dan pada 2010 memenangkan gelar tunggal tur ATP pertamanya di Delray Beach, mengalahkan Ivo Karlović di babak final.