Original sentence: He regained the World No.However, this became impossible when rival Robin Söderling defeated Federer 3–6, 6–3, 7–5, 6–4 in the quarterfinals
Edited sentence: He retained the World No.However, this was derailed when rival Robin Soderling defeated Federer 3–6, 6–3, 7–5, 6–4 in the quarterfinals.No other man has accomplished this feat