By James Standley

Murray failed to hit the heights he managed against Roger Federer

Andy Murray followed up his win over Roger Federer with a nervous victory against Fernando Verdasco in the Dubai Championships second round.

A single break in the sixth game saw Murray take the first set 6-3 but, with Murray struggling on serve, Verdasco won the second set 6-3.

The Scot claimed the initial break in the third and although Verdasco broke back, Murray won the tie-break 7-5.

Unseeded Murray will play fifth seed Nikolay Davydenko in the last eight.

News conference: Andy Murray

Davydenko ensured four of the top five seeds made it into the quarter-finals, following world number one Federer's first-round demise.

Second seed Rafael Nadal swept past Russian Mikhail Ledovskikh 6-4 6-0 and Novak Djokovic saw off veteran Frenchman Fabrice Santoro 6-3 7-6 (7-3).

Nadal will meet Andy Roddick who beat Paul-Henri Mathieu 6-3 6-3, while Djokovic faces Igor Andreev, a surprise 6-3 6-4 winner over Richard Gasquet.

Fourth seed David Ferrer booked a meeting with fellow Spaniard Feliciano Lopez with a 3-6 7-5 6-1 win over Belgium's Olivier Rochus.

606: DEBATE Well done AM but that was not very convincing against an opponent who is ranked 30 in the world prasinethee

Murray - whose serve was so impressive in his win over Federer - struggled on Wednesday in windy conditions.

"I was struggling to find the right shots and was mis-hitting a lot of balls - I'm just glad to get through in the end," he said.

"To play a match after winning against Federer was always going to be difficult mentally. It was really tough because there was no pressure against Federer and today I was expected to win.

"Davydenko is a tough match, he's been in the top 10 for the past few years but I've got a good record against him."

Murray, who beat Federer in three sets on Monday, had won both of his previous meetings with world number 30 Verdasco.

Games went with serve until 3-2 in the first set and, although Murray had to save a break point in the fifth game, he promptly claimed the decisive break in the very next game.

Verdasco saved the first three break points but on the fourth he cracked, double-faulting to give Murray a 4-2 lead.

The Scot had to save two break points in his next service game, some big serving getting him out of trouble, and two games later he closed out the first set in style with his third ace, only to soon find himself in trouble in the second set.

A poorly-executed drop shot at break point down in his first service game, followed by a mid-court lob, enabled Verdasco to claim his first break of the match.

Murray forced two break points in the Spaniard's next service game and although Verdasco managed to fight him off that time, he fell apart in his next service game to gift Murray the break and get the set back on serve.

However, Murray's serve, so impressive in his first round win over Federer, was rapidly falling apart.

He was only making 36% of his first serves, down from 61% in the first set, and Verdasco was immediately able to break back and take a decisive lead in the set.

Murray was looking sullen and frustrated by his inability to impose himself and he had to fight off a break point in the third game of the decider, his serve briefly flickering back into life to save him.

The Scot was fighting himself as much as his opponent but over the next couple of games he showed signs of better form and managed to break in the sixth game, only to immediately hand the break back as his form again dipped.

Both players had brief periods of ascendancy and a nervy Murray was lucky to survive a break point at 5-5 as the match went to a tie-break.

The Scot took an early 3-0 lead in the tie-break and when Verdasco blazed a second serve return yards wide to go 4-1 down the writing was on the wall.

Murray soon found himself with four match points, only to make errors on the first three occasions.

His fourth chance came on his serve and after an agonisingly long rally Verdasco cracked, hitting a forehand yards over the baseline to hand Murray a 6-3 3-6 7-6 win.