Complex sentence: By April 1997 he had already won his first major, the 1997 Masters, in a record-breaking performance, winning the tournament by 12 strokes and pocketing $486,000.
Split into simpler sentences: By April 1997 he had already won his first major, the 1997 Masters. Woods won this tournament in a record-breaking performance, winning by 12 strokes while pocketing $486,000.