I've been looking at some stats from Ivo Karlovic. For 2010 it is like this: 1st serve percentage: 65% 1st serve win percentage: 85% 2nd serve win percentage: 49% in every 100 service points he wins: 0.85 x 65 + 0.49 x 35 = 68.40 out of points won by Karlovic If Karlovic went for a 1st serve on every 2nd serve he gets he'll win: 65 x 0.85 + 35 x (0.65x0.85) =74.6 out of 100 points won by Karlovic I'll explain: He'll still hit 65 first serves in. He'll still win 85% of those. Which is already 55 percent of points on his serve. Of the remaining 35 points, instead of 49% on a normal second serve, he'll win 85% of 65% of those (presuming he's strong enough mentally to get as many first serves in at the second time of asking as he normally would) and lose the remaining points (35% of 35 points) on a double fault. My Statement: Karlovic should never hit a second serve and just go for another first serve. Thoughts?