World number six Tomas Berdych was given a tough workout by Nikolay Davydenko at the Barcelona Open on Tuesday before seeing off the former number three 3-6 7-5 6-4 to secure a berth in the last 16.
Czech Berdych, who had a bye into the second round and is seeded three on the clay at the Real Club de Tenis, served poorly against the 31-year-old Russian, who had won nine of their 11 previous matches.
After having his service broken twice in losing the first set, Berdych managed to turn things around to edge the second before lifting his game in the decider and sealing victory with a ninth ace.
The 27-year-old will play the winner of the match between Bulgaria's Grigor Dimitrov, the 14th seed, and 2004 champion Tommy Robredo of Spain for a place in the quarter-finals.
Latvian qualifier Ernests Gulbis provided the surprise of the day when he thumped former world number seven and 12th seed Fernando Verdasco of Spain, who won the event in 2010, 6-3 6-4.
World number five Rafa Nadal begins his bid for an eighth Barcelona title in nine years with a second-round clash against unseeded Argentine Carlos Berlocq on Wednesday.
Recently back from seven months out with a knee injury, Nadal is seeded second and beat top-seeded Spanish compatriot David Ferrer, the world number four, in the final in 2008, 2009, 2011 and 2012.
Ferrer plays his second-round match against Russian qualifier Dmitry Tursunov on Wednesday.
(Writing by Iain Rogers in Madrid, editing by Pritha Sarkar)