Depends on the 5.0 and his skill set. Not all 5.0s are equal. I'm pretty good friends with a 5.0, former DI college singles player, who's played against and hit against pro women. He said the big difference is Errani's serve. A 5.0/5.5 player with a good serve and forehand would give SE problems. ... Take the serve out of it and it's no contest, SE wins on skill, fitness, movement, etc.