The No. 2-ranked Nadal is aiming to go one better than Roger Federer and win a men’s-record 21st Grand Slam singles title.
He didn’t play for Spain at the ATP Cup last week and has been troubled by stiffness in his lower back.
“Well, it’s been a tough 15 days for me. I had some issues with the back,” Nadal said in his postmatch interview. “I needed to survive today. That’s what I did.
“Straight sets — that’s what I need.”
Russia’s ATP Cup-winning combination had relatively easy first-round wins.