Not sure about that on a grass surface. Boris Becker at his best on grass in my opinion was better than Lendl at his best although Lendl could beat him. Anyway he had a lot of rivals in Connors, McEnroe, Wilander, Becker and Edberg. Wilander and Lendl had a lot of great finals like the 1988 US Open final. The battles with Connors and McEnroe were tough too.