At strategy "Edit" form tick option to use favorite positions from before in play.
Then set strategy to bet on player one by using "Selection conditions->Bet type by RUNNER position" rule, set it to Back first runner by position.
Use "Selection conditions->Selections filter" and set it to allow betting only on 1st favorite.
Then use tennis rule to check for set score 0:1.
This will work for first player only. For second player you will need to create second strategy that will bet on runner by position 2 and check score 1:0.
Both strategies should be set to bet on match odds market.
Please test it in simulation mode.