After bowing to her opponent when the clock ran down, Wu jumped into her coach's arms before taking a Chinese flag thrown from the crowd and doing a lap of honour.
"It feels really good to be an Olympic champion again. It's not just my work that brought me here, it's the whole of China," she said after her 8-1 win.
"I spent a long time training and it was such tough work. But it was what I was waiting for, a second consecutive gold medal."
Enrique had been the aggressor on her road to the final but could not pin Wu down. The Chinese fighter's balance and leg speed gave Enrique problems and she was picked off from distance time and again.
The Spaniard said she thrived on the support from the crowd and was not too disheartened to miss out on the title.
"I'm a bit disappointed of course that I couldn't get a gold medal, but an Olympic silver medal is just fantastic. I'm so happy to have it," she added. "I was going for the gold but I think I was a bit tired after the semi-final."
Thailand's Chanatip Sonkham and Lucija Zaninovic of Croatia won bronze medals through the repechage competition.
Zaninovic's match against Mexican Jannet Alegria Pena went to sudden death, where the Croatian triumphed 7-5.
"I'm super happy with winning an Olympic medal but I would have preferred gold," she said. "I tried to avoid the sudden death if possible but it's sweeter when the fight ends this way."