Several things :
1- the CPU and human controlled players use the same rules to run & accelerate.
Level 3, 4 & 5 have a small handicap, Level 0 (Incredible) has a small bonus, and Level 1 & 2 have exactly the same limit (according to the Speed & Tonicity skills).
Although, there's 1 thing the CPU can do and u cannot : accelerate in any direction. You, you can only accelerate in 8 direction : up, left, down, right & the 4 diagonals.
2- If the CPU is too strong for u, then use a lower difficulty level. Use the "LevelFraction" skill to set it precisely.
3- When u do several left/right accelerations, your opponent will very likely strike shorter shots ; then, u _HAVE_ to go inside the court to hit a winning acceleration, either using the regular one or the short one.
It's not needed all the time, but it often very really ease the process of kill ur opponent
4- When u do left/right accelerations, if you do them far enough of your opponent, u greatly improve the chances to see a weaker reply or a fault.