Table:
text: Ace (tennis)
Men
Men
Aces Player Opponent Event Sets_
113 John Isner Nicolas Mahut 2010 Wimbledon 5
103 Nicolas Mahut John Isner 2010 Wimbledon 5
78 Ivo Karlović Radek Štěpánek 2009 Davis Cup 5
55 Ivo Karlović Lleyton Hewitt 2009 Roland Garros 5
54 Gary Muller Peter Lundgren 1993 Wimbledon 3
51 Ivo Karlović Daniele Bracciali 2005 Wimbledon 5
51 Joachim Johansson Andre Agassi 2005 Australian Open 4
50 Roger Federer Andy Roddick 2009 Wimbledon 5
50 Chris Guccione Olivier Patience 2005 Wimbledon 3
50 Grégory Carraz Tomáš Zíb 2004 Andrézieux challenger 3
49 Richard Krajicek Yevgeny Kafelnikov 1999 US Open 5

text: Ace (tennis)
Men
Men
Aces Player Opponent Event Sets_
48 Marc Rosset Arnaud Clément 2001 Davis Cup 5
48 Ivo Karlović Ivan Dodig 2011 Australian Open 5
48 Nicolás Almagro Olivier Rochus 2012 Wimbledon 5

Question: Which opponent had fewer than 50 aces in the 2001 Davis Cup of Men?