(CNN) -- World number one Rafael Nadal recorded his 35th win in 37 matches as he beat big-serving American Taylor Dent at the Cincinnati Masters.
The Spaniard triumphed 6-2 7-5 in one hour and 24 minutes to set up a third round clash with Frenchman Julien Benneteau, who beat Stanislas Wawrinka, of Switzerland.
Nadal cruised through the first set but had to recover from 4-2 down in the second to prevent a decider.
Second seed Novak Djokovic booked his place in the next round with a 6-3 7-5 victory over fellow Serbian Viktor Troicki.
Djokovic, who has lost in the final at Cincinnati two years running, will now face Argentina's David Nalbandian after his opponent, American John Isner, retired from their match though injury.
After the match, Djokovic told reporters that he was struggling with his serve: "You need to have a decent serve, which is going to give you some free points, and, especially on a court like this, which is quite a bit faster than the one we played on last week [in Toronto]."
"[My serve] gets up and down. It's not what I want, but I'm slowly getting the old serve I had. I had a good motion and, when I won a grand slam, I was serving really well, around 200km per hour on average, which was great, and with a lot of precision.
"These days I'm struggling a bit, but it's a mental thing. It's going to get to me sooner or later."
Third seed Roger Federer advanced when Uzbek Denis Istomin suffered a right foot injury and retired after only 28 minutes with 16-time Grand Slam champion Federer leading 5-2.
Fourth seed Andy Murray was taken to three sets but eventually triumphed over Frenchman Jeremy Chardy 6-3 6-7 6-2.
Number eight seed Mardy Fish, from America, beat Spain's Fernando Verdasco in straight sets thanks to two tie-breaks.
Elsewhere, Spaniard David Ferrer beat American Sam Querrey 7-5 6-2 while France's Richard Gasquet got the better of Michael Berrer from Germany 6-4 6-2.