With the victory Thursday, Nadal improved to 13-3 in five-set matches. He won all 20 points on his serve in the final set.
Haase came into the match Thursday ranked 151st, with two career victories on grass and a 2-6 record in Grand Slam tournaments. But he dominated with his serve early and finished with 28 aces.
Nadal is playing at Wimbledon for the first time since winning the 2008 title. He missed last year's tournament because of knee tendinitis but may be poised for a strong run after winning his fifth French Open title this month.