Great Britain's women held off a fightback from South Korea to win 5-3 and claim their second straight victory in the Olympic hockey tournament.
Britain, who beat Japan 4-0 in their opener, took a 3-1 lead before the Koreans levelled in the second half.
Late strikes from Georgie Twigg and Chloe Rogers ensured Britain maintained their 100% start to Pool A.
Striker Alex Danson was taken off on a stretcher after an awkward fall but it was later assessed as not serious.
"In terms of those qualities you look for from a high-performing team I was absolutely delighted," said Great Britain coach Danny Kerry.
"It is the Olympic Games and you have performances like that but it is how you come out of them that is the thing.
"When the pressure came on they did what they did. It would've been easy to go on the back foot and let Korea roll us over and we didn't and I am delighted for the girls."
Britain began the match without captain Kate Walsh, who is recovering after having surgery on a broken jaw suffered in the opening match.
But they did not seem too troubled, with Nicola White, Crista Cullen and Dansen giving them a comfortable cushion early in the second half.
The Riverbank Arena was then stunned by two goals in quick succession from Han Hyde Lyoung and Park Mi Hyun, testing the nerves of the British players, but they regained the initiative through Twigg and Rogers.
"We showed real true grit and determination to get back," said Twigg.
"Three-three is never easy with about nine minutes to go and we went and put two more goals in. This team is going to go far in this tournament. It's a really exciting time for us."
Great Britain's next match is against Belgium on Thursday at 19:00 BST. Earlier in Pool A, the Netherlands beat Japan 3-2 before China and Belgium drew 0-0.
In Pool B, South Africa lost 4-1 to New Zealand, the United States beat Argentina 1-0 and Australia saw off Germany 3-1 in the late match.