Reigning champions Wales saw off a promising Italian side 23-15 thanks to tries from Alex Cuthbert and Scott Williams.
Italy showed huge improvement from their substandard outings last November, exciting centre Michele Campagnaro grabbing a brace with two opportunistic tries.
History beckons for Wales; the objective of becoming the first side to complete a hat-trick of consecutive titles has been drilled into their squad over the last few weeks.
This, though, was an unconvincing performance. Wales worked harder in defence than attack and struggled to sustain phases going forward, although they did control the breakdown.
This is a special group of players without doubt, perhaps whose true destiny will be the Rugby World Cup next year, but they were worryingly flat in the second half.
Italy fielded their most experienced pack in Test history but had three 20-year-olds in the backline, still trying to find that balance between set-piece excellence and exciting back play. Judging by this game they appear to be leaning towards the latter.
Such was their decline at the back end of 2013 it was easy to forget they defeated both Ireland and France in last year's competition. Going against tradition, the Italian scrum struggled, but the backs were dangerous and exciting. Campagnaro at outside centre sparkled.
Two crucial lapses at either end of the first half though were Italy's undoing, highlighting the need for composure as well as plenty of enthusiasm. Wales are too good to cough those chances up. The Italian scrum disintegrated, Wales winning the penalties in that area and at the breakdown as the match wore on to secure victory.
Angelo Esposito endured every debutant's nightmare early on, rushing across to cover Rhys Priestland's grubber kick and missing it completely to allow Alex Cuthbert to scoop up and dive over in the corner with only three minutes on the clock.
Italy got on the board thanks to Tommaso Allan's simple penalty in an even opening quarter, Wales' supremacy at the breakdown just handing them the territorial advantage.
Halfpenny's 28th-minute strike opened up a 10-3 lead for the champions but Italy were dogged for large swathes of the first half, keeping the door shut on Wales and working hard to chase their kicks and put the hosts under pressure.
Sergio Parisse couldn't gather Edoardo Gori's clever cross-field kick for what would have been a impressive try as the Azzurri maintained their tenacious start.
It faltered just before the break - Scott Williams releasing Jamie Roberts to bust through Alberto Sgarbi's tackle before receiving the inside ball to go over, handing Wales a comfortable 17-3 cushion. Italy's energy and enthusiasm had worked against them as Sgarbi leapt out of the defensive line too soon.
Campagnaro bagged an excellent try for his first, his pass to Leonardo Sarto coming under scrutiny from the TMO but he raced after the winger's kick to bring Italy within nine points of the lead.
Italian rugby currently weighs on the shoulders of the 20-year-old Allan and his missed conversion and penalty were vital, particularly when Italy were enjoying the majority of possession.
Wales were left to soak up attacking waves and bide their time, Priestland nearly pouncing with a winding run to the corner only for his pass to find a man in blue rather than red.
Sam Warburton received a rousing reception following his introduction off the bench, political differences put to one side, as the Wales scrum continued to dominate in the eyes of the referee. It generated a second penalty for Halfpenny, helping Wales breath easier at 20-8.
Halfpenny's breathing was considerably less easy a few minutes later when Campagnaro pounced with an interception try, narrowing the deficit to five.
The Wales full-back though added another penalty - again won by great work from the hosts at the breakdown - to keep the Italians at arm's length. It was far from a masterclass from Wales, but a job done.
Man of the Match: With two tries and causing plenty of danger for the Welsh defence, Michele Campagnaro gets the nod for a very impressive performance in midfield.
Moment of the Match: A pick for Campagnaro again, with his interception of Halfpenny's pass seeing him streak away for a long-range try to narrow the scoreboard late on and leave Wales sweating.
Villain of the match: No real nasty stuff worth mentioning.
Tries: Cuthbert, Williams
Cons: Halfpenny 2
Pens: Halfpenny 3
Tries: Campagnaro 2
Wales: 15 Leigh Halfpenny, 14 Alex Cuthbert, 13 Scott Williams, 12 Jamie Roberts, 11 George North, 10 Rhys Priestland, 9 Mike Phillips, 8 Toby Faletau, 7 Justin Tipuric, 6 Dan Lydiate, 5 Alun-Wyn Jones (c), 4 Luke Charteris, 3 Adam Jones, 2 Richard Hibbard, 1 Paul James.
Replacements: 16 Ken Owens, 17 Ryan Bevington, 18 Rhodri Jones, 19 Andrew Coombs, 20 Sam Warburton, 21 Rhys Webb, 22 James Hook, 23 Liam Williams.
Italy: 15 Luke McLean, 14 Angelo Esposito, 13 Michele Campagnaro, 12 Alberto Sgarbi, 11 Leonardo Sarto, 10 Tommaso Allan, 9 Edoardo Gori, 8 Sergio Parisse, 7 Mauro Bergamasco, 6 Alessandro Zanni, 5 Marco Bortolami, 4 Quintin Geldenhuys, 3 Martin Castrogiovanni, 2 Leonardo Ghiraldini, 1 Michele Rizzo.
Replacements: 16 Davide Giazzon, 17 Alberto De Marchi, 18 Lorenzo Cittadini, 19 Joshua Furno, 20 Francesco Minto, 21 Tobias Botes, 22 Luciano Orquera, 23 Tommaso Iannone.
Referee: John Lacey (Ireland)
Assistant Referees: Glen Jackson (New Zealand), Francisco Pastrana (Argentina)
TMO: Iain Ramage (Scotland)
Assessor: Clayton Thomas (Wales)
by Ben Coles