Complex sentence: Over that 21 year period, she was ranked in the U.S. top 10 fourteen times and went undefeated in ten Wightman Cup competitions, winning her ten singles and nine doubles matches.
Split into simpler sentences: Over that 21 year period, she was ranked in the U.S. top 10 fourteen times. DuPont was undefeated in ten Wightman Cup competitions, winning her ten singles and nine doubles matches.