Murray lacked fluency and consistency against his Italian opponent
Andy Murray was made to work hard before beating Andreas Seppi 7-6 (7-4) 7-5 to book a spot in the World Tennis Tournament quarter-finals in Rotterdam.
The Briton required a tie-break to settle the opening set and was down 3-1 in the second before regaining his composure to secure the win.
World number one Rafael Nadal was also stretched in overcoming Bulgarian teenager Grigor Dimitrov 7-5 3-6 6-2.
Murray will next play France's number 55 in the world Marc Gicquel on Friday.
"There were a lot of errors from both sides in the first set. The standard was not good. Both of us started playing better and by the second set it was really tough," Murray said.
"Of course he had nothing to lose, but it was a battle. I played my way into the match. As there were so many long rallies I was able to improve my rhythm from the baseline."
Seppi won their only previous match at the Nottingham Open in 2006.
Murray quickly grabbed the opening two games and it seemed it would be a routine victory for the 21-year-old world number four.
The 24-year-old Italian raised his energy levels and forced a lacklustre Murray into a number of errors to take the first set to a tie-break.
Seppi lost the opener but he took full advantage of an increasingly wayward and tempestuous opponent and took a 3-1 lead in the second.
In an intriguing battle the pair slugged it out to 5-5 but Murray stayed firm and broke Seppi's serve before squeezing through to take the victory.
Nadal struggled through the first two sets of his clash with Dimitrov as his usual flow of winners dried up on the quicksilver Ahoy Arena courts.
Murray pleased at second set display
The 17-year-old world number 478 had two break points in the fifth game of the decider, but Nadal recovered to deuce with a raking forehand and some powerful baseline play.
The junior US Open and Wimbledon champion was then toiling with fatigue and a leg strain, and Nadal responded to force a break in the next game and move into a decisive lead.
Nadal then peppered the tramlines with a series of excellent shots to polish off the match.
He advances to face Jo-Wilfried Tsonga who squeezed past Russian Dimitry Tursunov 7-6 (8-6) 6-2.
Other second-round winners were France's Gael Monfils, Croatia's Mario Ancic, and Murray's next opponent Gicquel - a late entry into the tournament to replace injured Swede Robin Soderling.