Nadal avoided a repeat of his first-round defeat in the doubles competition
Rafael Nadal returned to action after his Australian Open win with a laboured 4-6 6-2 7-5 defeat of Simone Bolelli in the ABN Amro World Tennis Tournament.
Despite failing to replicate his recent sparkling form, Nadal did just enough to see off the determined Italian.
He will now face Grigor Dimitrov in the Rotterdam competition's second round.
Elsewhere, third seed Nikolay Davydenko suffered a shock departure, while Jo-Wilfried Tsonga and Michael Llodra came through tightly fought matches.
World number 37 Bolelli was an outsider before the start, but the unfancied Italian shocked his celebrated opponent early on as he converted a break of serve to take a 4-2 lead.
The Melbourne champion looked as if he was feeling the effects of his five-set marathons against Fernando Verdasco and Roger Federer last week and struggled in vain to strike back and restore parity.
Bolelli stubbornly held on to his serve to close out the first with five aces to his name and suggest he could make the Spaniard the highest-profile victory of his career.
The Ahoy Arena saw Nadal's worst tournament showing of last year when he departed in the second round and, after his meek surrender of the opening set, he initially looked unlikely to improve this time around.
But his familiar scurrying baseline play suddenly returned to break Bolelli to love in the sixth and eighth games and whisk the second set out of his grasp.
A gritty third set performance from Bolelli kept the outcome in doubt as he clung valiantly to Nadal, but his resolve and serve was finally broken as the pressure finally told late on.
Simone Bolelli made light of his world 37 ranking to push Nadal all the way
Davydenko was outplayed by France's Julien Benneteau who humbled the out-of-sorts Russian 6-3 6-2 with a superb performance.
Sixth seed David Ferrer was another casualty, coming unstuck at the hands of the 2007 tournament winner and world number 62 Mikhail Youzhny, whose dominant service game earned him a 6-2 3-6 6-2 win and a quarter-final against either Mario Ancic or Gilles Simon.
Ancic and Simon won their tournament openers against Philipp Kohlschreiber and Rainer Schuettler respectively, while Tsonga battled his way past home favourite Jesse Huta Galung, 7-6 7-6.
Defending champion Llodra bounced back from the loss of the opening set to defeat Croatia's Ivo Karlovic 4-6 6-3 6-4 and set up a clash with France's Gael Monfils.