The 2017 US Open champion won in straight sets to set up a semifinal with Madison Keys.
The American hasn't dropped a set in three rounds at Roland Garros.
Kiki Bertens also advanced, setting up a third round clash with Kerber.
The No. 4 seed needed nearly four and a half hours and a balky leg from the American to advance.
The former US Open brushed aside recent injury doubts with a first round win at Roland Garros.
Frenchman Nicolas Mahut indicated after his loss to Juan Martin Del Potro that he may have played his last singles match at Roland Garros. Speaking after...
Serena Williams was forced to produce a strong effort, but found good form from the start and dispatched Kristyna Pliskova 7-6, 6-4 in the first round...
The No. 8 seed rallied from a two set to none hole to see off a testy Robin Haase.