Halep 2.26, Kerber 1.78
Head to heads are 4-4. Most recent Oct 2016, ind hard, Kerber in 2. They played 5 times in 2016. Kerber won 4 of them. Halep leads 3-1 on hard courts.

Kerber tricked me in the 4th round by coming close to being beaten by Hsieh. In Kerber’s quarter final with Keys, as Keys had been playing at a high level I gave her a chance to take at least a set against Kerber. As it turned out Kerber tore her a new one, losing just 3 games.
Halep went 3-0 down against Pliskova in their quarter final but then won the next 9 games and 12 of their remaining 14 games. Halep had her own poor match which was against Davis in the third round. Halep saved 3 match points in their deciding set which she eventually won 15-13.

Kerber has stronger stats in the tournament. We have some value on Halep to take a set. Maybe Kerber peaked too soon with her form against Keys. I see a good chance of this going to 3 sets. They have only had three 3 set matches in the past. Halep won all 3.
Lay Kerber if she breaks first or wins set 1.