Brazil's Marcelo Melo and his partner Poland's Lukasz Kubot play against US player Ryan Harrison and New Zealand's Michael Venus during their men's doubles semi-final match on day seven of the ATP World Tour Finals tennis tournament at the O2 Arena in London on November 18, 2017. / AFP PHOTO / Glyn KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)
Brazil's Marcelo Melo (R) and his partner Poland's Lukasz Kubot (L) talk between points against US player Ryan Harrison and New Zealand's Michael Venus during their men's doubles semi-final match on day seven of the ATP World Tour Finals tennis tournament at the O2 Arena in London on November 18, 2017. / AFP PHOTO / Glyn KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)
US player Ryan Harrison (R) returns as his partner New Zealand's Michael Venus (L) stands ready against Brazil's Marcelo Melo and Poland's Lukasz Kubot during their men's doubles semi-final match on day seven of the ATP World Tour Finals tennis tournament at the O2 Arena in London on November 18, 2017. / AFP PHOTO / Glyn KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)
Brazil's Marcelo Melo (L) returns as his partner Poland's Lukasz Kubot (R) stands ready against US player Ryan Harrison and New Zealand's Michael Venus during their men's doubles semi-final match on day seven of the ATP World Tour Finals tennis tournament at the O2 Arena in London on November 18, 2017. / AFP PHOTO / Glyn KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)
Brazil's Marcelo Melo (R) covers the net as his partner Poland's Lukasz Kubot (L) returns against US player Ryan Harrison and New Zealand's Michael Venus during their men's doubles semi-final match on day seven of the ATP World Tour Finals tennis tournament at the O2 Arena in London on November 18, 2017. / AFP PHOTO / Glyn KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)
