Complex sentence: Muguruza has also enjoyed substantive success in doubles, winning five titles with her most significant results being the final at the 2015 WTA Finals and the 2014 French Open semifinals.
Split into simpler sentences: Muguruza has also enjoyed substantive success in doubles, winning five titles. Among her other significant results being the final at the 2015 WTA Finals and the 2014 French Open semifinals.