Venus Williams set up a second round encounter with her sister Serena at the WTA Italian Open in Rome, following a marathon 7-5, 3-6, 7-6(4) victory over Elise Mertens. It took the 38 year-old American more than three hours and nine match points to see off the Belgian world number 20. The second round match will be the 31st meeting between the Williams sisters - Serena leads the head-to-head series 18-12. Their last match on red clay came in the 2002 French Open final, won by Serena. In their last match in Rome, Venus won their second career meeting way back in the 1998 quarter-finals.