Frentzen progressed to German Formula Opel Lotus in 1988 in the Junior Team of former Formula One driver Jochen Mass, who had been impressed by Frentzen's performances in Formula Ford.
Frentzen progresou á Fórmula alemá Opel Lotus en 1988 no Equipo Junior do ex piloto de Fórmula Un Jochen Mass, quen quedara impresionado polas actuacións de Frentzen na Fórmula Ford.