As we all well know, when playing competitively in a tournament, portions of your standing are dictated by the kindness of your opponent. What we must endeavor to do is to 'convince' your opponent that you are indeed worthy of all 10 sportsmanship points each round. Often times this can be easier said than done. An opponent that you give a fun game to and allow them to increase their overall standings in the tournament is more likely to give you more points than the opponent that you unmercifully tabled giving them zero points.
So how can you go about winning and increasing your opponents standings at the same time? A beginning to this is quite easy actually. The key is to win the game, but minimize the points you take away from your opponent. If the mission calls for kill points, and the bonus points are rewarded to keep the enemy out of your deployment zone, for example, then there is no reason for either player to go for the opponents deployment zone. If you are winning the game, why do you need to interfere with the opponents ability to claim the bonus points?! There is simply no reason to do so!
In many games I have witnessed, players simply don't understand that an action can amount to no reward and only takes away from the opponent. However, by leaving the bonus points to the opponent you increase their overall score which is a feat which will probably be reflected in their post game scoring of your sportsmanship....
So to sum up the moral of the story: Win your game, but only do so through the missions parameters. Do not act to take points away from your opponenet if you have nothing to gain.