Longest winning streaks on the ATP Tour in the Open era (since 1968):
46-Guillermo Vilas (July-Sept. 1977)
44-Ivan Lendl (Sept. 1981-Feb. 1982)
42-John McEnroe (Jan.-May 1984)
41-Bjorn Borg (Oct. 1979-April 1980)
41-Roger Federer (Aug. 2006-March 2007)
35-Bjorn Borg (May-Aug. 1978)
35-Thomas Muster (April-June 1995)
35-Roger Federer (June-Nov. 2005)
34-x-Novak Djokovic (Dec. 2010-May 2011)
32-Rafael Nadal (May-Aug. 2008)
31-Bjorn Borg (May-Aug. 1979)
31-Ivan Lendl (Aug.-Nov. 1985)
30-Jimmy Connors (July-Oct. 1978)
29-Bjorn Borg (Oct.-Nov. 1977)
29-Ivan Lendl (Jan.-March 1986)
29-Pete Sampras (Feb.-May 1994)
28-Guillermo Vilas (Oct. 1977-Jan. 1978)
28-Jose-Luis Clerc (July-Sept. 1981)
26-Ivan Lendl (Feb.-April 1982)
26-John McEnroe (Sept. 1982-Jan. 1983)
26-Andre Agassi (July-Aug. 1995)
26-Roger Federer (Aug. 2004-Jan. 2005)
25-Jim Courier (April-June 1992)
25-Roger Federer (Feb.-April 2005)
x-active streak