The 19-year-old Ioane, a member of New Zealand's national sevens squad, took the ball from the halfway-line in the 65th minute and burst through the Sharks defence before sprinting away to touch down in the right corner.
Flyhalf Ihaia West's conversion gave the Blues a two-point lead and the home side held on for their third win of the season, keeping their slender playoffs hopes alive.
Back to square one for Sunwolves after Cheetahs mauling
Barrett burst helps Hurricanes rout Rebels
Super Rugby results and standings
Struggling Guildford given time off by Waratahs
Folau switched to centre as desperate Waratahs seek win
Former Blue Haiu dies of cancer aged 31
Brumbies to honour Vaea at home game after shock retirement
CHEETAHS 92 SUNWOLVES 17
South Africa's Cheetahs ran in 14 tries as they inflicted a humiliating defeat on the Sunwolves from Japan in Bloemfontein on Friday.
Wing Sergeal Petersen and number eight Paul Schoeman each scored a hat-trick of tries as the Cheetahs completed their biggest ever victory in Super Rugby and a double over the Sunwolves this season.
Just a single point separated these sides when they met in round three in Singapore, but the Sunwolves looked weary at the end of a three-match South African tour as they played with little structure or commitment and allowed too many soft scores.
REBELS 13 HURRICANES 38
Beauden Barrett scored two tries in an 18-point masterclass as the Wellington Hurricanes humbled the Melbourne Rebels 38-13 in a Super Rugby match on Friday.
The Hurricanes ran in six tries to two to post their fifth win of the season and shore up fourth place in the Australasian conference to keep their playoffs hopes alive.
CRUSADERS 32 JAGUARES 15
Fullback Israel Dagg scored two tries and set up another on his return from injury as the Crusaders stormed to a dominant bonus-point 32-15 win over the Jaguares in Christchurch.
Andy Ellis, Richie Mo'unga and Kieran Read scored the other tries for the home side, with number eight Facundo Isa and Gonzalez Iglesias touching down for the visitors.
(Compiled by Ian Ransom; Editing by Patrick Johnston)