Re: On-court coaching
Hate it, part of what I enjoy about tennis is the fact that it's 2 players (or 4 in doubles) out there alone, trying to beat each other. Part of the skills of a top tennis players should be being able to deal with the emotional/mental highs & lows of a match, knowing how & when to change tactics if necessary etc, if they can't do that then it's something they should work on off court, not during a match with the help of a coach or whatever. If you always ask someone else how to do it, you'll never work it out for yourself.
Petra KvitováWimbledon - 11, 14
Roland Garros - 09 US Open - 04