The Chinese duo had finished second in 2015 and 2016 at the season's showpiece event but a superb display of acrobatics proved too good for their rivals.

Skating to Simon & Garfunkel's Bridge Over Troubled Water, their personal best free skate score of 150.83 points added to a 232.06 overall total.

It came after Sui, who fell with a mistimed landing midway through, underwent surgery on both her feet early last year.

They won by just 1.76 points over Germany's Aliona Savchenko and Bruno Massot at the Hartwell Arena.

"It was a very moving performance and I think the audience could feel our emotion and our story in this programme," said 24-year-old Han.

Evgenia Tarasova and Vladimir Morozov of Russia took bronze with 219.03.

Javier Fernandez also made a perfect start in his bid for a third consecutive men's singles world title after a near-immaculate short programme earlier in the day.

The Spaniard, who followed bronze medals in 2013 and 2014 with victories in 2015 and 2016, scored 109.05 points as he performed to "Malagueña".

He landed a quadruple toeloop-triple toeloop combination, plus a quad salchow, to comfortably take the lead.

The score comfortably improved upon his 104.25 personal best set when winning the European title in January and was within two points of Yuzuru Hanyu's world record.

Shoma Uno of Japan lies second with 104.86 going into the free skate on Saturday (April 1).

Three-time world champion Patrick Chan lies third with 102.13.

Jin Boyang of China lies fourth with 98.64.

Japan's Olympic gold medallist Hanyu had to settle for fifth with 98.39.

The World Championships is being held in Finland’s capital for the third time, having also taken place there in 1983 and 1999.

In total, 193 skaters from 36 ISU members are competing.