Tennis Tracker: Lehecka takes down Tiafoe in straight sets, Fritz ties it up for USA
WTA roundup: Haddad Maia survives in Sao Paulo, Mertens & Kudermetova stunned in Mexico
Alex De Minaur vows to 'make life difficult' for Belgian Davis Cup opponents
Holger Rune has painted his racket black to keep a secret during Davis Cup clash