 Complete the following phrase:  In 1990, Senna took a commanding lead in the championship with six wins, two second-places, and three thirds. With Prost gone to Ferrari, he also had a new teammate in Austrian driver and friend Gerhard Berger. Among his victories were the opening round on the wide streets of Phoenix, in which he diced for the lead for several laps with Jean Alesis Tyrrell before coming out on top, and in Germany, where he fought Benetton driver Alessandro Nannini throughout the race for the win. Senna won six races, including another Monaco win, and as the season reached its final quarter, however, Alain Prost in his Ferrari rose to the challenge with five wins, including a crucial victory in 