<div><p>Power server John Isner has put his hand up to help rescue America's under-manned Davis Cup challenge this year.</p><p>The United States are without both their Cup stalwarts, Andy Roddick and James Blake, for this year's team competition and captain Patrick McEnroe is looking for replacements for the opening round against Serbia in March.</p><p>Isner, along with Sam Querrey, Mardy Fish and Taylor Dent, are in contention to play.</p><p>He enhanced his chances by reaching the fourth round of the Australian Open where he was beaten in straight sets by Scottish fifth seed Andy Murray on Sunday.</p><p>The towering ISner won the lead-up Auckland tournament and three rounds at the year's opening Grand Slam to push his name forward for Davis Cup duty for the March 5-7 tie in Belgrade.</p><p>"If I'm selected to play, I'm going to go," Isner said.</p><p>"This is a great start to the year. I would have liked to have kept on going in this tournament.</p><p>"But I won my first ATP tournament last week and to make the final 16 here, I won eight matches in a row at this level, it's a great accomplishment.</p><p>"I know that if I can continue that, this type of consistency, my ranking is going to continue to climb."</p><p>Isner has reached a career-high ranking of 28 after finishing last year at 34, some 111 places higher from 2008.</p><img src="http://admatch-syndication.mochila.com/images/ad.gif?aid=67699896&bid=informcom" /></div><div id="copyright"><div>

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