Question: Who had a better single career ranking, Rohan Bopanna or Jim Grabb ?

Context paragraphs:
Jim Grabb: Jim Grabb (born April 14, 1964) is an American former professional tennis player.  He was ranked the World No. 1 doubles player in 1989 and in 1993.  Grabb's best singles ranking was World No. 24, a ranking he achieved in February 1990.

2012 Gerry Weber Open – Doubles: Rohan Bopanna and Aisam-ul-Haq Qureshi were the defending champions but Bopanna decided not to participate. <br>

2012 If Stockholm Open – Doubles: Rohan Bopanna and Aisam-ul-Haq Qureshi were the defending champions but Bopanna decided not to participate. <br>

2013 BNP Paribas Masters – Doubles: Mahesh Bhupathi and Rohan Bopanna were the defending champions, but Bhupathi decided not to participate.  Bopanna played alongside Édouard Roger-Vasselin.

2016 Dubai Tennis Championships – Men's Doubles: Rohan Bopanna and Daniel Nestor were the defending champions, but chose not to compete together.  Bopanna played alongside Florin Mergea, but lost in the first round to Nestor and Radek Štepánek.  Nestor and Štepánek lost in the quarterfinals to Łukasz Kubot and Marcin Matkowski. <br>

2009 LA Tennis Open – Doubles: Rohan Bopanna and Eric Butorac were the defending champions, but Bopanna did not participate that year. <BR>Butorac partnered with Scott Lipsky, but lost in the first round to Denis Istomin and Leonardo Mayer. <BR>Bob Bryan and Mike Bryan won in the final 6–4, 7–6 against Benjamin Becker and Frank Moser.

2014 Open 13 – Doubles: Rohan Bopanna and Colin Fleming were the defending champions, but Bopanna chose not to participate.  Fleming played alongside Ross Hutchins, but lost in the quarterfinals to Marin Draganja and Mate Pavić. <br>

2016 MercedesCup – Doubles: Rohan Bopanna and Florin Mergea were the defending champions, but Bopanna chose to compete in s'Hertogenbosch instead.  Mergea played alongside Horia Tecău, but lost in the semifinals to Marcus Daniell and Artem Sitak.

Rohan Bopanna: Rohan Bopanna (born 4 March 1980) is an Indian professional tennis player.  His singles career high ranking was World No. 213 in 2007 and his career high ranking in doubles was World No. 3 on 22 July 2013.  Recently, most of his appearances in professional tournaments have been in doubles matches.  He is a member of the Indian Davis Cup team since 2002.  In 2010, he finished as a runner-up in doubles at the US Open, partnering with Aisam-ul-Haq Qureshi.  He won the 2017 French Open - Mixed Doubles title with Gabriela Dabrowski of Canada becoming the fourth Indian player to win a Grand Slam title.

Gabriela Dabrowski: Gabriela Dabrowski (Polish: "Dąbrowska" ; born April 1, 1992) is a Canadian professional tennis player.  She reached her highest WTA singles ranking of 164 on November 3, 2014 and her highest doubles ranking of 18 on September 11, 2017.  She won the 2017 French Open mixed doubles title with Rohan Bopanna, becoming the first Canadian woman to win a senior Grand Slam title.

Supporting paragraphs: Rohan Bopanna Jim Grabb
Answer: Jim Grabb