Nadal will now face seventh seed Fabio Fognini after the Italian beat France’s Adrian Mannarino 6-2, 7-5.
Juergen Klopp’s side, runners-up to Manchester City last season, swept aside fellow German Daniel Farke’s team with their trademark attacking verve, taking a 3-0 lead inside 28 minutes.
There was no such drama in Toronto, where Williams broke Osaka for a 5-3 lead in the first and closed out the opening set with a service winner.
Nkwe, who currently coaches the Bizhub Highveld Lions, said he was looking forward to the opportunity.
Such is the rivalry between the trans-Tasman neighbours that New Zealand coach Steve Hansen sees retaining the trophy as second only to defending their world title in his priorities for 2019.
It was seven minutes after the visitors opened the scoring through outside centre Alwayno Visagie who ran a good angle to go through and put them 7-0.
It would be the first match between Naomi Osaka and Serena Williams since the Japanese star defeated her childhood idol 6-2, 6-4 in last year's US Open final
Belgian Lukaku, who spent two years with United after a £75 million move from Everton, joined Inter for a fee reported to be around 80 million euros.
Serena Williams and Japan's Naomi Osaka booked a rematch of last year's US Open final in the WTA Toronto quarterfinals after straight-set triumphs Thursday.
South Africa top the table heading into their final game but home captain Pablo Matera told the Springboks to expect a battle.
