The battle opened with the Spanish artillery firing into the Portuguese positions, opening gaps in the first line of infantry. The Spanish cavalry then charged the Portuguese left flank, succeeding in overruning several units. The Portuguese infantry organized themselves into squares to fend off the cavalry, but this left them vulnerable to the Spanish artillery. The Duke of Schomberg's men gathered around some buildings on the left flank of the Portuguese army, using the structures and a vineyard wall to break up the advancing mass of Spanish cavalry. The Portuguese cannon fired repeatedly into the ranks of Spanish cavalry, inflicting many casualties. As the first Spanish charge retreated, Meneses ordered his first line back and consolidated it into the second line. When a Spanish cannonball killed Sir Francisco da Silva Moura, the commander of the Portuguese contingent of the second line, Meneses took command in person.