They have played twice. Stephens won their last match which was in March last season. She won in straight sets. Kerber won on a hard court in 2012 in 3 sets. Both the matches were at Indian Wells.
This season before this week Stephens has either lost her first match of the week or she has won the tournament. She won titles in Acapulco and Auckland. She played well in her last match but gave up break leads in the first and third sets.
Kerber had a tough first match this week and needed a third set tie break to beat Arruabarrena but has looked strong since. She is the defending champion this week.
There is value on Stephens at the start but I think Kerber comes through in 3 sets.