Top seed and title favourite Novak Djokovic had to dig deep into his reserves to fend off a determined Radek Stepanek and reach the third round at Wimbledon.

A win against Andy Murray and run to the semi-finals at the Aegon Championships at Queen's Club marked Stepanek down as a player in form on grass, and he tested Djokovic close to the limit.

Eventually the Serbian found a way to beat perhaps the most dangerous of the unseeded players in the draw, coming through 6-4 6-3 6-7 (7/5) 7-6 (7/5) on Centre Court.

Stepanek slipped twice in the fourth-set tie-break to give up the early advantage, which he clawed back but then handed straight back to Djokovic.

At 5-2 it looked all over, but Stepanek had trailed by the same margin in the third-set tie-break and remarkably, taking successive points off his opponent's serve, he got back on level terms again.

Yet a volley into the net handed Djokovic a match point behind his own serve, and when the 2011 champion went across court with a forehand Stepanek feared the worst as it landed.

The ball was called out by a line judge, but Djokovic challenged that verdict immediately. Stepanek, engaging in the mild farce he peppered the match with, got down on his knees, hands clasped together, to offer a prayer.

But there was no salvation for the 35-year-old Czech, who reached the quarter-finals in 2006, as Hawk-Eye showed the shot had clipped the outside of the line for a clean winner.

The pair embraced warmly at the net and Stepanek's hope of an upset was gone.

Djokovic said: "I was two sets up and had some break-point chances in the third and I should have closed it out in the third set tie-breaker, but credit to him for fighting.

"He's 35 years old but he's moving very well. Grass is probably his most preferred surface. He performs really well on the big stages as you saw.

"He loves to engage the crowd, he's an entertainer, and it was fun from one side to be part of a great thrilling match, but on the other side I should not have complicated my own life this way.

"It was annoying I came to Wimbledon without any official match practice and my first-round match went just over hour, so I didn't have a lot of match play.

"I was quite focused and tense before the match because I knew what was on the other side of the net. I knew his ability and his quality.

"It was a difficult one but I'm glad I stayed hanging in there mentally and managed to win."

Andy Murray pulled off the most emphatic Wimbledon win of his career to race into the third round.

The defending champion was in sublime form on Court One, needing just an hour and 24 minutes to see off Slovenian Blaz Rola 6-1 6-1 6-0.

Murray had never previously dropped fewer than six games in a match at the All England Club, while it was his most one-sided result at a slam since losing one game to Alberto Martin at the Australian Open in 2007.

Murray had begun his title defence in fine style with a comfortable win over David Goffin and Rola was another unknown quantity.

The world number 92 was playing in only his third grand slam tournament.

Rola's nerves were obvious as he allowed Murray to break serve in the opening game, throwing in a double fault and a number of mis-hits.

The 23-year-old Slovenian only began to play on the tour full-time this season after going to university in the United States and has risen up the rankings quickly.

A big forehand is his main weapon and he had Murray in a spot of trouble at break point down in the fourth game, but the Scot saved it with an ace.

Murray then showed his full repertoire of skills to break again for 4-1 and took his third set point in Rola's next service game.

After saving a second break point with an ace in the opening game of the second set, Murray made it six games in a row with yet another break of the Rola serve.

It was turning out to be a rather chastening experience for Rola, who simply could not hold his serve.

The world number 92 finally stopped the run of games against him at nine but Murray promptly served out the set 6-1 with a lovely dinked backhand.

Rola's hopes of mounting the most unlikely of comebacks were dealt another blow at the start of the third set.

Having missed two break points, Murray played a stunning rally to move 1-0 ahead, ending it with a crisp forehand winner down the line.

The 27-year-old was in complete control, showing off all facets of his game and giving Rola a thorough runaround.

The Slovenian continued to have the odd glimpse on the Murray serve and created a third break point of the match at 3-0, but it went the same way as the others.

Rola then served successive double faults to leave Murray serving for the match, and he clinched it with a love game, ending on a delightful drop shot.

Grigor Dimitrov also eased through, the number 11 seed's straight-sets triumph over Australian Luke Saville was almost as routine as Murray's own success, the Bulgarian coasting through 6-3 6-2 6-4 on Centre Court.

Latvia's Ernest Gulbis was the first big hope to crash out on Wednesday, the 12th seed losing out to world number 90 Sergiy Stakhovsky 6-4 6-3 7-6 (7/5).

Big-serving South African Kevin Anderson moved past Edouard Roger-Vasselin in four sets, a 7-6 (7/0) 1-6 6-3 6-4 winner.

Ukraine's Alexandr Dolgopolov dismissed German Benjamin Becker 6-7 (7/4) 7-6 (7/0) 6-3 6-4, the 21st seed marching on with little issue.

Becker's compatriot Tim Puetz gained little joy from 16th seed Fabio Fognini, the Italian driving through 2-6 6-4 7-6 (8/6) 6-3.

Outspoken Australian Marinko Matosevic enjoyed a fine run at Queen's and was aiming to reproduce that attacking form at Wimbledon.

The Bosnia-born 23-year-old was unable to edge out wily Jeremy Chardy however, the Belgian grinding through 6-7 (7/5) 7-6 (9/7) 7-6 (11/9) 4-6 7-5.

Wild-card entrant and former Australian Open finalist Marcos Baghdatis was unable to reach the third round, overcome by Argentinian Leonardo Mayer.

The South American world number 64 undid Cypriot crowd favourite Baghdatis 7-6 (7/4) 4-6 6-1 6-4.