Golf: Consistency key to emulating Federer and Serena - Woods

Three-time US Open champion Tiger Woods aims for his 16th major title at the US Open at Winged Foot this week but admitted on Tuesday that it's becoming harder to win as he gets older. Woods astounded the sporting world when he won the Masters last year after years off the course due to injury and personal problems. But his form has been patchy since then and he paid tribute to evergreen tennis veterans Rafael Nadal, Roger Federer and Serena Williams - all still at the top of tennis despite their advanced years. Woods is aiming to add a fourth US Open title to those he won in 2000, 2002 and 2008.