Task: Explanation
Input (English): Marc Polmans (born 2 May 1997) is a South African born Australian tennis player. Polmans won the 2015 Australian Open – Boys' Doubles title with fellow Australian Jake Delaney, defeating Hubert Hurkacz and Alex Molčan in the final, 0–6, 6–2, [10–8]. He reached the semi-final of the 2017 Australian Open – Men's Doubles with Andrew Whittington. Question: Marc Polmans, with Andrew Whittington, reached the semi-final of a tennis tournament where who were the defending champions? Answer: Jamie Murray and Bruno Soares
Output (English):  He reached the semifinal of the 2017 Australian Open – Mens Doubles with Andrew Whittington.