Furlong opened the scoring in the third minute and goals from Sam Ward and Stuart Rushmere allowed GB to cruise to a 3-0 lead at half-time.
Furlong, 32, scored again in the third quarter while Spain’s Jordi Bonastre slotted a consolation goal.
The women’s match was much closer fought, with China’s Ma Ning giving her team an early lead.
GB hit back with goals from Isabelle Petter and Sophie Hamilton before Tan Jinzhuang responded to leave the teams level at the break.
Britain twice took the lead in the final quarter – through Sarah Robertson and Grace Balsdon – but two Gu Bingfeng goals meant the fixture finished 4-4.
The match headed to a penalty shoot-out which Britain clinched 6-5 with Petter scoring the winner.
Both GB teams are in action again in London on Thursday, when the women host the United States (17:45 BST) and the men play Ireland (20:00).
