Playing the Score vs. Playing the Point
1. Andre Agassi was known to be the best front runner. When he got ahead by a break or a set, he started playing better and better. For him, that was playing more aggressive and slightly riskier tennis.
The previous set he'd won gave him confidence, and now he was going for more. This approach worked very well for Agassi, and he often finished matches quickly after winning the first set. His US Open statistics in the last few years were something like 54:1 when he won the first set. That is, he lost only one match in which he won the first set.
2. Roger Federer and other top players often play a risky down-the-line service return, even on a first serve, when down 40-0 in a game. They do this mostly on faster courts and not so much on clay.
They do this because they feel that winning a return game from that score is very unlikely, so they might as well try a risky winning return. If it does score, they have surprised their opponent and perhaps unsettled him. Plus, they have boosted their own confidence.
3. Some players raise the risk of their whole game. An example of this was a match between James Blake and Roger Federer at the Championships in Shanghai. Blake played well in the first set but lost 6-0. He raised his risk factor in the second set: playing much closer to the baseline, hitting the balls on the rise, counter attacking when in trouble, and playing more down-the-line shots.
Blake played the score and had nothing to lose. He had played tactically correct tennis in the first set, but Federer was just too good. So Blake decided to go for it, and managed to win 3 games in the second set.
Another example of this tactic was when Andre Agassi won the French Open in 1999. He was a set and two breaks down against Carlos Moya and realized that he couldn't play a sensible clay court tennis match with one of the best clay courters. So Agassi started taking chances and going for the big shots. He won that match and eventually the French Open title.
4. Big servers like Pete Sampras, Boris Becker and Goran Ivanisevic almost always went for big second serves when up 40-0. They played the score, and they knew that if that big second serve (which was actually the same as their first serve) went in, they had an excellent chance of winning the point.
You must clarify why are you playing and what you really want. If you want to have it all--the showing off, the experimenting, the practice and the win--you are very likely to fail. Be more realistic. How about just winning the match? Isn't that good enough?
Then decide whether you are going to choose the "fight for every point" approach or the "play the score" approach. If you are going to play the score, it may take quite some time to correctly judge the situation and play accordingly with success.
And be aware that all these decisions are part of the overall tennis strategy that you are going to adopt in your play. When you are clear on which approach you are going to take, it's time to prepare yourself with more detailed tennis strategies and tactics.