JACK NICKLAUS: It was the start of the final round of the 1980 U.S. Open at Baltusrol. I had played all 54 holes with Japan's Isao Aoki, and we were tied for the lead. The first hole was a narrow par 4 (converted from a par 5 for the Open), and fans 20 feet deep lined both sides of the fairway.
To focus, I told myself what I always tell myself when the pressure is at its greatest: Complete the backswing.
Jack Grout had taught me this many years earlier. He'd say, "Get collected, Jackie boy." The natural tendency is to rush the transition under pressure. You start down before you have a chance to set the club at the top. Thinking of finishing the backswing takes care of that.
At the top, I want the shaft parallel to the ground (above). I also want the club pointing at or to the right of the target, never left. Because my shoulder turn was greater than 90 degrees, my club pointed right of the target (across the line), just slightly. That allowed me to swing into the ball from inside the target line.
I nailed my opening tee shot, went on to play one of the rounds of my life -- a 68 with Isao nearly matching my every shot -- and won the tournament by two strokes.
JIM FLICK: The most critical part of the swing is impact, but the most difficult to execute is the transition. You must learn to change direction from the ground up -- first planting your left heel or rolling your left ankle -- and you can do this only if you complete the backswing.
The most common fault is the over-the-top move caused by the right shoulder getting too active at the start of the downswing -- the club comes into the ball steeply from outside the line. The result is a pull or weak slice.
Completing the backswing results in a more consistent transition. Your arms now have room to drop to the inside for a shallower approach and a stronger, more reliable impact position.
NICKLAUS writes articles only for Golf Digest.
FLICK, a longtime Golf Digest Teaching Professional and PGA Golf Professional Hall of Famer, worked with hundreds of amateurs and tour players including Jack Nicklaus.