Russian teenager Kournikova received a code violation for being coached from the sidelines during her fourth-round win against doubles partner Barbara Schett.
Kournikova's mother Alla had been calling out advice to her when she trailed 3-4 in the second set, a spokesman for tournament referee Peter Bellenger said.
Australian star Lleyton Hewitt got his hefty fine for abusing the chair umpire during his third-round loss to Spaniard Carlos Moya.
Hewitt fired an audible obscenity at umpire Rudi Berger when the official over-ruled line-call in the ninth game of the tense fifth set.
Racquet abuse
These are just the latest in a long line of players hit with code violations in the tournament so far.
France's Fabrice Santoro has been ordered to pay $5,000 for unsportsmanlike behaviour towards an official after his second-round loss to Canadian Daniel Nestor.
Several players have been cited for racquet abuse including Germany's David Prinosil whose $2,000 fine was reduced to $1,000 on appeal.
Switzerland's Marc Rosset and American Jan-Michael Gambill were hit with a $500 bill for the same offence.
Ukraine's Andrei Medvedev has been fined $1,000 for verbal obscenities during his loss to Sweden's Andreas Vinciguerra.