The 20-time grand slam champion gives his assessment of his Serbian rival ahead of their first clash since 2016.
A 46th career meeting with Novak Djokovic awaits in Sunday's final.
The Serbian is one win from the career sweep of Masters 1000 events.
Former champions Agnieszka Radwanska and Petra Kvitova will face each other in the first round of the Connecticut Open.
Simona Halep targets her second final in a row and Novak Djokovic is a win away from his first Masters 1000 final in 15 months.
Milos Raonic and Pablo Carreño Busta fell to quarterfinal defeats.
Simona Halep won her seventh consecutive match with a straight sets victory over Ashleigh Barty.
How will Nick Kyrgios fair against new world No.3 Juan Martin del Potro?
These are the two must-see matches to follow at the Western and Southern Open on Thursday.
Kei Nishikori's blockbuster clash with Stan Wawrinka headlines Wenesday's play at the Western and Southern Open.
The action heats up on day two in Cincinnati as Roger Federer and Serena Williams play their second round matches.
Pablo Carreno Busta joined Kei Nishikori in the second round of Cincinnati after a three set win over Richard Gasquet.
Following a thrilling week in Canada, the draws in Cincinnati this week are even more loaded.
Both singles world number ones will play for championships on Sunday, in rematches of tournament finals from earlier this year.
Simona Halep reached the final in Montreal with a straight forward 6-4 6-1 win over Ashleigh Barty.
Simona Halep is upset at the tournament organisers at the Coupe Rogers after she has only 17 hours to recover from her quarter-final win over Caroline...
Who will reach the final of this year's Rogers Cup?
Can Rafael Nadal and Simona Halep continue their winning runs in Canada?
Juan Martin Del Potro has withdrawn from the Rogers Cup in Toronto due to left wrist pain.
Almost all remaining players in the singles draws are on Wednesday’s Order of Play