Question: Who has a higher world ranking, Peter Fleming, or Oliver Marach?

Context paragraphs:
2010 Brasil Open – Doubles: Tommy Robredo and Marcel Granollers were the defending champions.  Robredo chose to compete in the 2010 ABN AMRO World Tennis Tournament instead.  Granollers partnered with Pablo Cuevas, and they won in the final 7–5, 6–4 against Łukasz Kubot and Oliver Marach.

2017 Abierto Mexicano Telcel – Men's Doubles: Treat Huey and Max Mirnyi were the defending champions, but lost in the first round to Oliver Marach and Fabrice Martin.

2011 BMW Open – Doubles: Oliver Marach and Santiago Ventura were the defending champions, but decided not to participate.  Marach competed in the Serbia Open instead.

2008 BCR Open Romania – Doubles: Oliver Marach and Michal Mertiňák were the defending champions, but Marach chose not to participate, and only Mertinak competed that year.

Oliver Marach: Oliver Marach (born 16 July 1980) is an Austrian professional tennis player.  His highest ATP singles ranking is world No. 82, which he reached on August 7, 2005.  His career high in doubles is world No. 8, set on October 18, 2010.

Peter Fleming (tennis): Peter Blair Fleming (born January 21, 1955 in Chatham Borough, New Jersey) is a former professional tennis player from the United States.  In his doubles partnership with John McEnroe, he won 52 titles, of which seven were at Grand Slams (four at Wimbledon, three at the US Open).  As a singles player, he peaked at World No. 8, winning three titles (including the 1979 Cincinnati Open).

2017 Aircel Chennai Open – Doubles: Oliver Marach and Fabrice Martin are the defending champions, but Marach chose not to participate this year and Martin chose to compete in Doha instead.

2010 Serbia Open – Doubles: Łukasz Kubot and Oliver Marach were the defenders of title, but Kubot chose not to compete this year and Marach chose to play in Munich instead.

Scheer (band): Scheer was an alternative metal band from County Londonderry, Northern Ireland.  It was first founded by PJ 'Doc' Doherty and Paddy Leyden however PJ after their first release, replaced by the band's then manager Peter Fleming.  The composition of the band was; Peter Fleming (Bass guitar), Paddy Leyden (Rhythm guitar), Audrey Gallagher (vocals), Neal Calderwood, (Lead guitar) and Joe Bates (drummer).

2014 Geneva Open Challenger – Doubles: Oliver Marach and Florin Mergea were the defending champions.  Mergea did not participate this year, Marach partnered fellow Austrian Philipp Oswald.

Supporting paragraphs: Peter Fleming (tennis) Oliver Marach
Answer: As a singles player, he peaked at World No. 8