Teenage lock Joel Kpoku came off the bench to give Saracens a seventh Premiership wins out of seven, which put them back at the summit.
Italy were hard done by in Padova on Saturday when Tito Tebaldi's first-half try was ruled out, according to Conor O'Shea.
Japan led 15-10 at half-time, but England scored three tries after the interval to avoid a huge upset at Twickenham.
Tonga showed some fight but Wales ultimately stormed to a 74-24 victory at the Principality Stadium.
Australia warmed up for their trip to Twickenham with a 26-7 victory over Italy, with Marika Koroibete scoring twice for the Wallabies.
Gloucester had Danny Cipriani back from a ban and the fly-half was instrumental in their bonus-point 36-13 win over Leicester Tigers.
Kieran Marmion thinks Auckland-born Ireland international Bundee Aki "won't hold back" when he faces New Zealand on Saturday.
Having joined the RFU in 2011 and been chief executive since September 2017, Steve Brown has announced he will leave at the end of the year.
Josh van der Flier will start as flanker against New Zealand after Ireland confirmed Dan Leavy would miss out through injury.
With Faf de Klerk on club duty with Sale Sharks, Embrose Papier will make his first South Africa start on Saturday.
A statistical look at Saturday's clash between Ireland and New Zealand at the Aviva Stadium.
Sale Sharks have moved to fill their need in the back row by signing Jean-Luc du Preez from Super Rugby side the Sharks.
France have made two changes to their starting line-up against Argentina, with Yoann Huget selected for the first time in a year.
Jordan Petaia will become Australia's youngest debutant for a decade in a much-changed side in Padova.
Full-back Rob Kearney and centre Garry Ringrose have recovered from injuries in time to start against New Zealand.
Wales coach Warren Gatland has made 14 changes for Saturday's international against Tonga, with Liam Williams selected for his 50th cap.