Common Mistakes in Tennis Matches Because of Lack of Rules Knowledge

Failure to call a let when a ball rolls into or behind the court

Please remember, that a ball rolling into your court from elsewhere is considered a distraction.  The correct thing to do is call a let and replay the point.  Even if you are about to hit an overhead to win the point, and a ball rolls in behind you, you and/or your opponent should call a let.  Once the point has ended, or there is no clear opportunity to get to a shot, if a ball rolls in the court, no let should be called.  

Not taking the point when your opponent touches the net

If a player, either with any part of their body or their racquet, touches any part of the net prior to the point ending (this is described by the ball bouncing twice, or hitting a permanent fixture after the first bounce or in the air), they LOSE the point.  Too many people let this go in their matches, and at the recreational level, it happens more often than you would think.  If a player touches the net, it happens BECAUSE the previous shot was so good that it forced your opponent to run into the net before catching their balance.  I have witnessed this in 3.0 matches in virtually every match I have ever watched.

Interrupting the serve of your opponent and not giving them a first serve

Once a player begins their service motion, any interruption, including balls rolling into the court, should result in the server getting a first serve,  This is even if the serve being interrupted was a second serve.  This happens too many times to count in league matches.  You must give your opponent a first serve if you interrupt their motion for any reason.

Playing a let when a line call cannot be made.

This is one of the most egregious offenses I have seen in league tennis and junior tennis.  You do not play a let.  If the player who is responsible for the line call cannot make one, the correct thing to do is call it in, and move on.  If a doubles team cannot come to a consensus on a line call, call it in and move on.  You do not, under any circumstances, play a let!

Playing a let when someone falls, gets injured, breaks a string, or drops their racquet

None of these situations should result in a let being called.  In each case the point is played to conclusion.  If the a team or player chooses to stop playing after their opponent falls, and the ball landed in on their side, the player or team who fell wins the point.  If your opponent falls, and your shot landed in on their side, you win the point.  The same is true for injuries.  The player who breaks a string must continue to play the point with the broken string.  The player who drops their racquet must pick up their racquet and continue to play the point.  No lets should be called in any of these circumstances.

Determining who serves first and what ends to play AFTER the warm-up

This one is the most common error made by players.  The mistake is warming up for your match, and after completing the warm-up, spinning the racquet to determine who will serve first and what end you will play on.  This is an incorrect procedure. 

The first thing you are supposed to do when you walk onto the court with your opponent(s) is spin the racquet to determine who will serve and on which end of the court you will play the first game.  Then you go to that end  and warm-up.  This way you warm up on the side of the court you will begin the match on.  

Not changing order of service after a set that results in a tiebreak.

If in the first set Player A or Team A served 1st, followed by Player B or Team B, and the set goes to a tiebreak with someone winning the set 7-6, the next set the order of serving is reversed.  In this case Player B or Team B would serve the first game of set two, followed by Player A or Team A.

Calling a let when you reverse a line call.

If you initially call a ball out, and then call it in after further review, you do not get to call a let.  You must give your opponent the point.  Once you elect to stop the point, you cannot play a let. If it turns out your line call was wrong, you must then give the point to your opponent(s)

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