In ATP round-robin tennis, how are the winner and second-place finisher of each group determined ...?

Question

... if players are tied both in matches and sets won and lost?

Answer 1

...
3) The final standings of each group shall be determined by the first of the following
methods that apply:
a) Greatest number of wins;
b) Greatest number of matches played;
c) Head-to-head results if only two (2) players are tied, or if three (3) players are tied,
then:
i) If three (3) players each have one win, a player having played less than all three(3) matches is automatically eliminated and the player advancing to the Single Elimination competition is the winner of the match-up of the two (2) players tied with 1-2 records; or
ii) Highest percentage of sets won; or
iii) Highest percentage of games won.
iv) If (i), (ii) or (iii) produce one superior player (first place), or one inferior player (third place), and the two remaining players are tied, the tie between those two players shall be broken by head-to-head record.
4) If ties still exist after the above procedures, the Steering Committee shall make the final determination.

Answer 2

a player will win the group if either he defeated all three players or at least two player by straight sets. the second place will be decided by the total win/loss percentage of games by the rest of players.