(CNN) -- Wales saw their hopes of a successful Six Nations title defense almost reduced to ruins in Rome, as substitute Tom Shanklin's 72nd-minute try saw them scrape a 20-15 victory against a battling Italy side on Saturday.
Tom Shanklin scores the decisive late try as Wales scraped a narrow victory over Italy in Rome.
Bottom-of-the-table Italy had conceded 100 points in losing successive games against England, Ireland and Scotland, but they almost produced one of the biggest shocks in Six Nations history on a tense afternoon at the Stadio Flaminio.
Wales coach Warren Gatland's gamble of making nine changes from the side beaten by France in Paris a fortnight ago almost backfired spectacularly before Shanklin got them out of jail, with his score following a first-half touchdown by wing Shane Williams, while fly-half James Hook kicked 10 points.
However, Wales will now need to record an emphatic victory over Grand Slam-chasing Ireland in Cardiff next Saturday -- possibly by 20 points -- to retain their title.
Italy took a sixth-minute lead through Andrea Marcato's opening penalty. Wales should have drawn level in the 21st minute, but Hook missed a penalty from in front of the posts.
Despite their dis-jointed display, Wales took the lead 13 minutes before the break when center Gavin Henson cleverly switched attacking direction and Williams scored a simple overlap try. Hook atoned for his earlier error by slotting the conversion, giving Wales a 7-3 lead.
But the visitors continued to make a host of errors, with the front-row conceding a second penalty, which Marcato scored to cut the deficit to one point.
Marcato completed his hat-trick five minutes before the break, after captain Alun-Wyn Jones took out Italy scrum-half Paul Griffen off the ball, giving Italy a shock 9-7 interval advantage,
A fourth Marcato penalty made the scoreline 12-7, before a Hook penalty for Wales narrowed the deficit again to two points.
An angled Hook penalty after 65 minutes inched Wales ahead, but the game remained poised on a knife-edge, with Marcato landing a fifth penalty to put Italy 15-13 ahead.
However, Shanlkin's late converted touchdown prevented the form guide being turned on its head and kept Wales in the hunt for a second successive title.