A last-minute drop goal by Duncan Weir gave Scotland a 21-20 win over Italy in Rome on Saturday.
Wales scored two tries and punished France through the boot of Leigh Halfpenny to keep their title hopes alive with a 27-6 win at Millennium Stadium on Friday.
With their first two hurdles successfully cleared, Ireland travel to Twickenham on Saturday sniffing the scent of a second Grand Slam in five years.
Italy will be confident of claiming another Six Nations win against Scotland in Rome.
Wales' defence of their Six Nations crown hangs in the balance as an in-form French side travels to the Millennium Stadium for a rare Friday night fixture.
Ireland have named an unchanged starting XV to take on England at Twickenham on Saturday.
Bath prop David Wilson will start in the front row against Ireland on Saturday at Twickenham.
Wales have made three changes to their starting line-up to face France on Friday, with Mike Phillips the notable omission.
France have made one injury-enforced change to their starting XV for Saturday's Six Nations clash with Wales.
Scotland coach Scott Johnson has dropped Ross Ford and Dave Denton from his side to face Italy on Saturday.