Eight months after the clash in Dublin was postponed because of the coronavirus pandemic, Andy Farrell's side secured the maximum points it needed to keep its destiny in its own hands in the battle for the title.
CJ Stander scored the opening try when Conor Murray was in the sin bin after debutant Paolo Garbisi's penalty gave Italy an early lead behind closed doors at Aviva Stadium.
Wing Keenan crossed twice in the first half and had a try disallowed prior to Will Connors touching down a debut score of his own to secure the bonus point, after Edoardo Padovani finished at the other end.
Johnny Sexton added a fifth try and booted 15 points, with Bundee Aki and Dave Heffernan also scoring before Garbisi went under the posts right at the end.
Ireland ensured it will face France – which, along with England, it is a point clear of – in Paris next Sunday (AEDT) on the final weekend knowing a bonus-point win will seal the title.
Murray was yellow carded inside three minutes for conceding a penalty just in front of his own line after Ireland were caught out by an incisive Italy break, Garbisi opening the scoring from the tee.
Ireland took charge despite being a man down, Stander crashing over from close range before Sexton was on target with a penalty and Keenan finished superbly after Robbie Henshaw – on for the injured Garry Ringrose – picked him out with a whipped pass.
Keenan had a try chalked off when James Ryan was penalised for obstruction, but he got on the end of scrum half Murray's kick to round off a swift break prior to the interval and Sexton converted expertly for a third time.
Italy did not do itself any favours as it gave away too many penalties, but Padovani plucked a stray pass from Sexton to race away and score 15 minutes into the second half.
Ireland had the bonus point in the bag soon after, though, Connors dotting down from the back of a driving maul after 61 minutes, then Sexton and Aki added further tries with Italy all at sea.
Heffernan scored Ireland's seventh from a set-piece and Garbisi marked his debut by scampering away for a try with time almost up in a one-sided contest.