No matter how great your strokes are, you’ll lose tennis matches if you’re always out of position. Club players work on their strokes but don’t spend enough time improving their footwork. You’ll find no better examples than Steffi Graf and Miloslav Mecir.
Both of them played tennis like billiards: They thought at least one shot ahead and they seldom overran the ball. If you have to take two or three steps in the wrong direction after contact, good contact won’t mean that much.