Andy Murray will be looking to extend his winning run to 22 matches and book his place in the semi-finals of the ATP World Tour Finals when he faces Stan Wawrinka on Friday afternoon. Murray has won both of his contests thus far in the John McEnroe Group, beating Marin Cilic in straight sets and then Kei Nishikori in a three-set epic.But he could still be eliminated if he loses to Wawrinka in straight sets and Nishikori beats Cilic in the groups other match in the evening on Friday. Murray v Stan: A battle royale Expect sparks to fly at Londons O2 Arena on Friday afternoon... Murray leads the head-to-head 9-7 against the Swiss, and has his sights set on a perfect final against Novak Djokovic that would decide the year-end No 1 ranking.I think for the tournament and stuff, for everyone interested in tennis, that would probably be the perfect way to finish the year, he said. Murray talked to Mark Petchey at the SkyPad after his victory over Nishikori For me, and Im sure for Novak, both of our goals would be to try to win the event. For him, whether thats by beating me, someone else, or, for me, if its winning against Novak or another player, it doesnt change for us as players.Murray was pushed to the limit by Nishikori in the longest three-set match in ATP World Tour Finals history, which lasted three hours and 20 minutes. John McEnroe Group W-L Sets Games Andy Murray 2-0 4-1 30-20 Kei Nishikori 1-1 3-2 27-23 Stan Wawrinka 1-1 2-2 19-24 Marin Cilic 0-2 0-4 17-26 He acknowledged afterwards that he was a bit tired, but added: You tend to feel it more the following day, in terms of stiffness and soreness in the body. I was in the ice bath after the match. That obviously helps make you feel a bit better. But 10-12 hours afterwards the body starts to stiffen up. Its positive I get a days rest.After losing his first match, Wawrinka kept his hopes of progressing alive with a 7-6 (7-3) 7-6 (7-3) victory over Cilic on Wednesday. Murray is one win from matching his career-best 22-match undefeated run from earlier this season, during which he won Queens, Wimbledon and Olympic gold All I know is if I want to have a chance to qualify, I need to win, he said afterwards. Thats all Im trying to do. Im going to try to play my best tennis, to beat the World No. 1. Its going to be a tough match.We played many times against each other. Hes playing his best tennis so far. Its going to be interesting. Im happy to play here in front of his home crowd. Im sure its going to be a great atmosphere.The only meeting between Murray and Wawrinka in 2016 was in the semi-finals of the French Open, with the world No 1 coming through in four sets. Watch highlights of Murrays win over Nishikori However, Wawrinka won their round-robin clash at the O2 last year 7-6 (7-4) 6-4.In the doubles match, Henri Kontinen and John Peers will be looking to make it three wins from three when they face world No 1 duo Pierre-Hugues Herbert and Nicolas Mahut.Hugues and Mahut are already eliminated after two defeats and could slip from the top of the rankings if Jamie Murray and Bruno Soares reach the final.Kontinen and Peers are already assured of a semi-final place, having won both their matches in straight sets.Watch the ATP World Tour Finals on Friday from midday on Sky Sports 1 HD or follow on www.skysports.com. Also See: One of Murrays best-ever matches Murray targets perfect final Wawrinka keeps hopes alive Stan sets sights on Murray Jim Cleamons Jersey . A knee to the thigh might have stung him the most, but his sixth straight double-double made up for the brief burst of pain. Brad Daugherty Jersey . Miikka Kiprusoff had just announced his retirement after a decade-long run in Calgary and it would be up to Berra and Ramo to fill the void. https://www.cheapcavaliers.com/ . DAmigo scored twice in regulation and added the shootout winner as the Toronto Marlies edged the San Antonio Rampage 5-4 in American Hockey League action. Tyler Cook Jersey . The Oilers come in having lost five in a row (0-4-1) and 16 of their last 20 games, dropping a 2-1 decision to the Vancouver Canucks on Tuesday. Cavaliers Jerseys 2021 .com) - Manchester City midfielder David Silva is expected to miss the next four weeks because of a calf problem. RIO DE JANEIRO -- It looks as if the water polo pool is turning green with envy.The mens Olympic tournament resumed Wednesday in green-tinged water after the diving pool at Maria Lenk Aquatics Centre turned a dark green the previous day. There was no sign of any water quality issues with the water polo pool during the first day of the womens competition Tuesday.A decrease in the alkaline level in the diving well Tuesday afternoon led to the green color, organizing committee spokesman Mario Andrada said. He added that the pool for water polo and synchronized swimming is being affected in the same way.We have treated both pools during the night and the alkalinity levels have already improved, Andrada said. We expect the color to be back to blue very shortly.Maybe not, according to a U.S. pool expert.Once you get behind, it gets hard to get back in front of it, said Jerry Wallace, chairman of the California Pool & Spa Association, a trade group.According to FINA, the world governing body for aquatic sports, water tanks ran out of some of the chemicals used in the water treatment process, causing the pH level to go outside the usual range, leading to the discoloration. Andrada and FINA said there is no risk to athletes competing in either pool.Just from TV and pictures on the computer, it looks more like an algae than alkaline problem turning the water green, Wallace said by phone from Sacramento, California.Andrada said algae also is an issue.The algae makes the water look green. We kept the same level of maintenance as we did before, but we had far more athletes, he said. We had more dirt in the water and that generated more algae.Wallace said if theres a reaction with iron in the water, the pool would turn a translucent green. But a murky green color, as seen in the diving pool, would indicate an algae issue. Wallace said some strains of algae will grow even in water that is balanced.If theyre cleaning the diving pool and then using the same tools in water polo, they could contaminate it, he said. Algae spoores can be transmitted.ddddddddddddThe warm and humid climate in Rio de Janeiro could be a factor, too.There are no such problems at the swimming venue, a temporary facility with its own filtration system. The diving and water polo pools are part of a permanent facility opened in 2007.The black lines at the bottom of the water polo pool were clearly visible as play continued throughout the day, and there was no evidence of the color affecting the action. But a couple players said they could tell the chemical mixture is off.They put way too much chlorine, U.S. captain Tony Azevedo said. The last quarter, I can barely open my eyes.Everyones obsessed with the green water. Who cares about the green water? Azevedo continued. Sometimes you can have green water, black water, it doesnt matter as long as its safe for us. You throw in too much chlorine, all of the sudden you cant see. These are things that, its the Olympic Games, you cant have that.Hungarian water polo player Gergo Zalanki got some drops for his eyes after an 8-8 draw against Greece. But he wasnt sure chlorine was the problem.Yes, it feels like that, but I dont know, Zalanki said between sniffles. In Hungary theres lots of water like this. It feels like lots of coloring, but theres something different.The Maria Lenk Aquatics Centre, named after the first Brazilian woman to compete in the Olympics, was renovated before the Rio Games. The major upgrades included new springboards, a refurbished medical center, new hydrotherapy baths and two new warmup pools. There is no mention of any update to the water treatment system in the venue description.Andrada said a test event at the facility did not account for increased use for longer periods during the Olympics.We probably failed to note that with more athletes the water could be affected in a different way, he said.---Jay Cohen can be reached at http://www.twitter.com/jcohenap ' ' '