In 1990, Gaby won the US open. In her team at that time, I believe there was a sports psychologist helping her with her game.
I don't think a psychologist was part of her team on a regular basis though which is a shame.
IMHO the mental side of her game was all that separated her from reaching no.1 and winning Wimbledon 1991 as well as countless other big matches.
On a side point, everyone talks about her match against Mary Joe in 1993, but they also met again at the US open QF in 1995.
In that match, Gaby led 6-1, 5-1 again and then started to inexplicably make a series of errors on numerous match points.
Mary Joe hit back to 5-3 and Gaby looked seriously stressed out (as stressed out as I was feeling !).
This time however she held it together and won before pushing Steffi in a very tight match in the semis, a match that she could have won.
I hoped that would put her back on track, but instead she got injured early in 1996 and retired <img src="frown.gif" border="0"> so I guess that shows how little I know.