Radek Stepanek gave defending champion Czech Republic a 1-0 lead over Argentina after breezing past Juan Monaco in straight sets.

Novak Djokovic wasted no time in sending Serbia into a 1-0 lead in the Davis Cup World Group semi-final with Canada, as he dispatched Vasek Pospisil 6-2, 6-0, 6-4 in the opening single rubber on Friday.

The world number one — who is fighting jetlag after arriving in Europe only 48 hours earlier following Monday’s US Open final — spent just one hour, 40 minutes in pounding out the win against the rookie semi-finalist side from North America.

Djokovic broke six times and fired 33 winners, winning the opening set with a five-game sweep at the Belgrade arena in the first-time meeting between the two countries.

Vasek committed nearly 50 unforced errors. “I did really well, considering I had one-and-a-half practices since getting here, said Djokovic. “I’m lacking freshness, so I tried to be extra committed from the start.

“Return of serve was key, I made him play another shot and the result was really, really good.

Janko Tipsarevic was trying to hand his 2010 champion nation a bigger lead as he faced Milos Raonic after losing three times to the Canadian on the ATP.

“I hope Janko feels a bit less pressure in his singles. We hope to be 2-0 up after the first day, that would be ideal,” said Djokovic.

Canada is hoping to continue this season’s fairy tale in the worldwide team competition after not having won a single World Group tie before knocking out Spain in the first round earlier in February in Vancouver.

In Prague, defending champion Czech Republic took a 1-0 lead thanks to US open doubles winner Radek Stepanek, who beat Juan Monaco 7-6 (7-3), 6-3, 6-2 in two and a half hours.

Stepanek was helped along by 13 aces, 38 winners and six breaks of serve.

“I have a huge responsibility,” said the 34-year-old. “I’m not only here for myself and playing Davis Cup for me is something indescribable. After reaching our goal last year, to play in front of our home crowd and family is special.” Argentina are playing without Juan Del Potro, who is sitting out the Davis Cup this season.

The Czechs were hoping to close out the day with another win at the O2 arena as ATP number five Tomas Berdych faced Leonardo Mayer.

In World Group playoff rounds, US Open champion Rafael Nadal beat Sergiy Stakhovsky 6-0, 6-0, 6-4 in Madrid as Spain took a 1-0 lead over the Ukraine. Surprisingly, it was the first time in 769 career singles matches that Nadal has won the first two sets without dropping a game.

In seaside Umag, on the Adriatic, Britain ended day one level 1-1 with Croatia after Andy Murray crushed 16-year-old US Open junior champion Borna Cornic 6-3, 6-0, 6-3 to spoil the teen’s Davis debut.

But Ivan Dodig produced a 6-3, 6-2, 6-3 result in the second rubber to keep the hosts in touch.

“The first five or six games were tough,” said Murray. “I wanted to make the points long, make it challenging for him ... He was solid, he fought for every point. When he gets physically stronger, he’s going to be a very tough player. The future is obviously very bright for him.” In Neuchatel, Switzerland advanced to a 2-0 margin against Ecuador through wins from Stanislas Wawrinka, US Open semi-finalist, and Marco Chiudinelli.

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