Novak Djokovic overcame the latest bump in the road on his seemingly  inexorable march towards the Wimbledon title with a straight-sets win over Denis Kudla.

The world number one extended his winning streak in grand slams to 17 matches and took another step towards a sixth Wimbledon crown, the third leg of the calendar-year grand slam, and a record-equalling 20th major title.

Djokovic can even still emulate Steffi Graf in 1988 when she won all four grand slams and gold at the Olympics – a feat yet to be repeated.

Not that this was an entirely straightforward win. The 34-year-old had described his second-round victory over Kevin Anderson as “flawless”, but he did not remotely hit those heights against American qualifier Kudla, a Tour journeyman ranked 114.

Instead there was plenty of irritation; double-faults here, a long forehand there – even a couple of service breaks and a third-set tie-break to negotiate.

The unforced error count was also up significantly on the six he registered against Anderson- this time he made 28.

Kudla stayed with the Serbian for the first nine games behind a solid service game, but Djokovic struck in the 10th to sneak the first set.

He won four games in a row across the end of the first and the start of the second, and although Kudla managed to break back Djokovic quickly regained his advantage.

But Kudla began feeding off the crowd inside the Court One outpost Djokovic had been downgraded to in favour of Brits Dan Evans and Andy Murray.

He gave them a glimmer of a comeback when handed a break after Djokovic double-faulted and went 3-0 up in the third.

But at 4-2 Kudla’s unforced error count increased at the wrong time and Djokovic pulled level.

Almost unheard of back-to-back double faults from Djokovic gifted Kudla a 3-0 lead in the tie-break.

But some trademark resolute Djokovic defence, and some poor shot choices from Kudla, saw the reigning champion through 6-4 6-3 7-6 (7).

Djokovic said: “I have to give credit to Denis for playing very well, the third set was very close. He’s a great guy and I wish him all the best.

“He was unlucky in the tie-break and somehow I managed to find a way to win. You have to give your maximum at what for me is the biggest tournament.”