Former world champion Mansell told BBC Sport: "Ayrton was our toughest rival."
"He would leave no stone unturned to get the utmost out of his car and his team."
"In the beginning, we were great enemies,"
"He wanted to win at all cost with everybody,
we knocked heads
quite a lot."
Mercedes driver said:
"Ayrton Senna was an incredible legend, who will be remembered and admired forever.