Big guns stay cool in the heat

But Wimbledon's lesser lights struggle in London scorcher

With everyone "feeling hot, hot, hot" at the All England Club on Wednesday, it was little wonder Novak Djokovic, Maria Sharapova and Serena Williams were eager to escape the Wimbledon furnace as quickly as possible.

Spectators sitting under the searing sun on Henman Hill were heard breaking out into the rock anthem that aptly summed up the hottest day of the year in London - with the mercury hitting 34 C.

Champion Djokovic was spared the worst of the heat on the partly covered Centre Court as he kept things simple in a 90-minute 6-4, 6-2, 6-3 second-round demolition job that ended the Wimbledon career of seasoned Finn Jarkko Nieminen.

It was Djokovic's sixth career win in seven meetings against the 33-year-old Nieminen and the two men exchanged a warm embrace at the net once their duel ended.

"It was his last Wimbledon so I congratulated him on a great career," said Djokovic.

His opponent in the next round, Australian Bernard Tomic, will be hoping the weather eases for their Friday showdown after complaining it was too hot.

"I was starting to get dizzy out there with the heat hitting me ... I was very dizzy out there," Tomic said after beating Frenchman Pierre-Hugues Herbert 7-6 (3), 6-4, 7-6 (5).

The blazing sun was the least of Sharapova's concerns.

"It's much much warmer in my hometown in Longboat Key, Florida," the Russian fourth seed said after subduing Richel Hogenkamp of the Netherlands, 6-3, 6-1.

But the 2004 champion was left red-faced as she fired three successive double faults to surrender her serve at 4-2 up in the first set but survived that blip to win eight of the next nine games.

Court Two also hosted the other half of tennis's golden couple with Sharapova's boyfriend, 11th-seeded Grigor Dimitrov, outlasting American Steve Johnson 7-6 (8), 6-2, 7-6 (2).

"Everyone was talking about it's hot, it's hot. To me it was just such good weather today," said the 2014 semifinalist who will next take on Frenchman Richard Gasquet.

Serena Williams might want to drop Marin Cilic and Ricardas Berankis a thank-you note after the duo's five-set thriller meant she did not have to step on to Centre Court until almost 7 pm.

However, the slightly cooler conditions did not mean the American world No 1 wanted to hang around longer than necessary as she took another step closer to winning her fourth successive major.

Serena whooped in delight after completing a 6-4, 6-1 pummeling of Hungarian Timea Babos.

"I'm definitely playing well, which I never say, but I had two really tough matches straight off the bat so I had to pick up my game," Williams said.

Venus Williams, also a five-time Wimbledon winner and a potential fourth-round opponent, went through, beating Yulia Putintseva of Kazakhstan 7-6 (5), 6-4.

Nishikori out

While US Open champion Cilic was relieved to be still standing following a 6-3, 4-6, 7-6 (6), 4-6, 7-5 win over Lithuania's Berankis, the same could not be said of fifth seed Kei Nishikori, who spared his battered body further punishment by pulling out of his second-round match against Santiago Giraldo with a calf strain.

"I was hurting too much," said the Japanese star, whose exit will be a huge blow back in his homeland.

Nishikori was not the only one needing medical attention, as a ballboy had to be wheeled off Court 17 after collapsing during American John Isner's 6-2, 7-6 (8), 6-4 win over Australian Matthew Ebden.

"I saw him on the ground. It was a very scary situation," said Isner. "I'm not a doctor, but it looked like an epileptic seizure. It was very scary. I have heard that he's doing much better, which is great."

French Open champion Stan Wawrinka was in cruise control during a 6-3, 6-4, 7-5 win over Victor Estrella but Milos Raonic was kept on Court One longer than he would have liked by the oldest man in the singles draw.

The Canadian seventh seed hurled down 29 aces to secure a 6-0, 6-2, 6-7 (5), 7-6 (4) victory over 37-year-old Tommy Haas.

Women's seventh seed Ana Ivanovic became the second top-eight woman to fall as the Serb followed third seed Simona Halep out of the tournament, beaten 6-3, 6-4 by 158th ranked American qualifier Bethanie Mattek Sands.

"I played a little too passive at the beginning. She got off to a good start which give her confidence and I think that's what made the difference," said Ivanovic.

Nick Kyrgios, the temperamental Australian who knocked out Rafael Nadal last year, ranted and raved at officials for the second match in succession as he beat Argentina's Juan Monaco 7-6 (5), 6-3, 6-4.

Heather Watson made sure Britain did not suffer a wipeout in the women's draw as she made it into round three with a 6-4, 6-2 win over Slovakia's former world No 5 Daniela Hantuchova.