Tennis players are dreamers. They constantly fantasize about the big win, the match in which every serve is an ace and every volley a putaway. The upset of a lifetime catapults them into the limelight. The weekender is redeemed.

There are craftier ways to realize this fantasy. Consider the upset of Wimbledon, 1975, when underdog Arthur Ashe whipped the supposedly unbeatable Jimmy Connors. Ashe's secret was planning ahead. He gave Connors what no other player had dared before: soft, short shots up the middle. Ashe won the biggest title in tennis by letting his opponent make make all the errors.

There is no reason you should not scout your opponent's game, too. If he thrives on hard drives, prepare to hit lots of soft underspin. If he has a single weakness -- say, missed overheads -- work on your lobs.

There is also nothing wrong with making a few notes. Did you see Roscoe Tanner reading from a small notebook during his nearmiss Wimbledon loss to Bjorn Borg this summer? He and his coach Dennis Ralston developed a game plan and Tanner rechecked his notes during changeovers.

We overheard the same Ralston giving advice last year at the U.S. Open to an almost unknown Californian named Butch Walts. "He doesn't like to have weak volleys hit right at him," said Ralston. Whereupon Butch Walts walked onto the center court at Flushing Meadow, hit all short volleys straight back at Argentine Guillermo Vilas and scored the upset of the tournament.

Besides such tactical planning, there is physical and mental preparation for the match. This time of year, the player who is in better shape -- the kind that comes from jogging an extra mile per day -- will have a distinct edge when the third-set woozies begin.

Get tough mentally. We're talking about winning tennis, not a few social sets. Insist on your rights and play strictly by the rules. Surprise your opponent with bulldog tenacity and calm self-confidence even when you're behind. Run down every ball and do anything to keep the ball in play (such as lobbing back his serves).

Remember what the pros tell themselves when they have been "bageled" (lost a set 6-0) by an awesome display of shots: "He can't go on hitting every line all day." They are usually right.

Q. When I go out against a better player, I'm so nervous I can't play as well as usual.

A. That's ridiculous. Remember that the pressure is all on him -- he's supposed to win. You have nothing to lose.

Q. I play as well as my friend except for one thing -- his cannonball serve, which always makes the difference. What can I do?

A. Don't try to match his serve with a blasting return. Just block the ball back or slice it so he will be drawn to the net. Let his pace do all the work. You should also vary your receiving position and challenge him by running around your backhand.

Q. My big weakness is my second serve. My regular partner always beats me with great returns, even if I serve to his backhand. What should I do?

A. Spend a few days practicing deep, spin serves. Meanwhile, try serving to his body.