Ireland need two wins to secure unprecedented back to back Six Nations Grand Slams after beating Wales 31-7 in a sometimes sloppy performance at Lansdowne Road on Saturday.
A late Tadhg Beirne try secured a bonus point win for the hosts, whose 11th successive Six Nations victory equalled the record held by England, who set it between 2015-17.
Ireland go to Twickenham to play England in a fortnight with Wales looking for their first win in this year's tournament at home to France.
Prior to kick-off there was an emotional moment as Tadhg Furlong cried during the national anthems, it being the first Test for him at Lansdowne Road since his father died late last year.
Ireland started well and their early dominance yielded a penalty which Crowley converted in the seventh minute.
The Irish came up trumps early in turning the ball over twice in rucks -- Bundee Aki and Andrew Porter earning the slaps on the backs from their teammates.
The home scrum had the Welsh one under all sorts of pressure and the hosts secured their first try of the encounter on the back of a penalty conceded by the visiting pack.
Crowley kicked for touch and from the ensuing line-out hooker Dan Sheehan touched down for his fourth try of this year's tournament.
Crowley converted from the touchline for 10-0 and the Welsh looked like they were staring at a very tough day at the office, although Ireland coach Andy Farrell cut a pensive figure in the coaches box.
He had reason to be as despite their territorial dominance Ireland were producing some scrappy errors.
However, Wales could not get outside their half, constant Irish pressure forcing them to give away penalties at will.
Referee Andrea Piardi had to talk to Wales captain Dafydd Jenkins after yet another infringement, though the skipper shot back at him "can you referee both sides please."
The Irish got on with the job and scored a second try as the Welsh defence cracked, James Lowe went over in the far right corner for his 14th try.
Crowley converted for 17-0.
That was that for the first-half as the Welsh failed to score in a half for the third time in this year's tournament.
Even more worrying for the visitors was they had conceded as many penalties -- nine -- as they had done in the first two matches.
However, they got a huge boost at the beginning of the second-half as the Welsh were awarded a penalty try and Beirne was sin-binned for breaking his bind.
At 17-7 all of a sudden it was game on.
Tension was growing, illustrated when Andrew Porter threw Gareth Thomas's loose boot deep into Irish territory, leaving the Welshman seething.
The Irish were now under the cosh, conceding four penalties inside the first 14 minutes of the second period.
However, Beirne redeemed himself immediately after his return as he turned the ball over with the Welsh pressing for the line.
Wales kept the pressure on but the Irish defence held firm and the outstanding Aki won a penalty to allow Ireland to clear their line.
Aki went over shortly afterwards but his joy turned to dismay as Piardi -- the first Italian to referee a Six Nations match -- referred it to the television match official who judged Henshaw to have knocked on during the move.
Finally the moment came in the 67th minute for the Irish to breathe easier after making heavy weather of it as Ciaran Frawley went over to mark his first Six Nations start.
Crowley converted for 24-7.
The Welsh spirit was undimmed and they were the side puffing away at the Irish line as the game wound down -- James Ryan sin-binned as the pressure told.
However, veteran prop Cian Healy saved them in forcing a turnover and the hosts perhaps undeservedly secured the bonus point at the death as Beirne went over.