A theory once prevailed that if the top 100 male tennis players were banned from touching a racquet for a month, the great American baseliner Andre Agassi would have been most likely to win the first tournament played thereafter. The reasoning was that Agassi, who retired last year, was the most gifted ball striker on the Tour and therefore the least dependent on practice for producing his best in matches. For the record, Agassi, though a humble champion, thought the theory was right. And the fact that four of his eight grand slam victories were Australian Open titles did nothing to undermine it. The first grand slam event of the year, the Australian Open poses a peculiar challenge to the players. Apart from a warm-up event or two, it's their first tournament for more than a month and follows a festive period often characterised by rest, (relative) overindulgence and an aversion to anything that reminds them of tennis. Thus, the Oz Open tends to favor two types of player the naturals like Agassi and surprise 2006 finalist Marco Baghdatis, and the toilers like 2002 winner Thomas Johansson who don't mind hitting thousands of balls over Christmas. Trying to distill this logic into a prediction of who'll win in Melbourne is always fraught, though perhaps less so in this era of Roger Federer, who's so far ahead of the rest in the ATP points race that in February he's certain to break Jimmy Connors' record for most consecutive weeks at No. 1 (160). Here are the 10 key questions and our best answers – about the Open fortnight, beginning Jan. 15. 1. Can anyone stop Federer? Of course. He's great, no doubt about it the best he's seen, says his veteran coach, Tony Roche. But there's still only an extremely fine line separating him and about 20 others. Some of these guys may never beat him because they don't believe they can or because there's something about their game that Federer devours. But there's at least a handful who could knock him off on a given day. Beaten five times last year, Federer is flesh and blood, prone to the odd burst of mishits and tension-induced mistakes. A slight injury, a blazing hot day, a rotten night's sleep any number of little distractions could level the playing field for a strong opponent, who might also just have a golden night like Russia's Marat Safin did in his semi-final against the Swiss in 2005. Federer's the percentage tip, but he's not unbeatable. 2. Who's most likely to beat him? That's a no-brainer: Rafael Nadal. Until last year's Wimbledon final a bizarre situation existed where the player being touted as perhaps the greatest of all time (Federer) had a 1-6 win-loss record against the world No. 2 (Nadal). Federer has prevailed the last two times they've played but both were close, tense affairs in which Federer at times appeared bothered by Nadal's belligerence, athleticism and astonishing shot-making from the baseline. Federer has the superior all-court game, but six times out of nine that hasn't been enough. "He always plays the same way," Federer has said of Nadal's ferocious left-handed topspin, "but he does that so well." The Spaniard also appears the slightly mentally stronger of the two. True, it's been on clay where he's tended to sting Federer. But in recent years Melbourne Park's Rebound Ace courts haven't played a lot faster than the red stuff and despite noises to the contrary they're apparently playing more or less the same this year. Nadal, at 20 five years younger than Federer, went off the boil in the second half of last year and hasn't started this year in sensational touch; he also withdrew with a groin strain from last week's warm-up event in Sydney. But Federer would still regard him as the main obstacle to a third Australian Open title. 3. Who else could win? Now ranked 26, Safin looms as a possibility courtesy of sheer talent (the Agassi factor) and a strong finish to 2006 in Russia's Davis Cup victory. Then again, it's easy to be biased toward a player who presents as charming, funny, candid, self-deprecating, philosophical and smart. Safin's compatriot, Nikolay Davydenko, who's risen to world No. 3 despite a body that appears more suited to chess, has been a quarter-finalist in Melbourne the previous two years and could sneak into the semis this time before many fans can say his name right. James Blake (U.S.), Tommy Robredo (Spain), Tommy Haas (Germany), David Nalbandian (Argentina) and Baghdatis are others to keep an eye on. 4. What about the huge-serving Andy Roddick? Hasn't he improved under coach Jimmy Connors? Connors' influence did seem to make a difference in the second half of last year, when Roddick made the final of the U.S. Open and later held three match points before losing to Federer in a round-robin match at the final event of the year, the Tennis Masters Cup in Shanghai. Roddick hits his serve and forehand as though his right arm were bionic. But some of us still need convincing that he's added a genuine Plan B to his repertoire, and that his answer to any kind of trouble isn't merely to stop hitting hard and start hitting harder. 5. What about a roughie? Try the in-form, fast-rising Scot Andy Murray. Federer lost only five times last year, four times to Nadal, once to the 19-year-old Murray, in straight sets at the ATP Masters in Cincinnati. Murray's coach is Brad Gilbert, a master at finding and exploiting the weaknesses of the game's best. 6. Does Lleyton Hewitt have no chance of becoming the first local champ in three decades? He has a very slight chance, though any optimism is based more on his remarkable competitive qualities than a clear-eyed assessment of his form. Now ranked 20, Hewitt is having far more trouble than he used to winning those tight matches against solid but unexceptional players, and as such could easily exit in any early round. For various reasons, he hasn't been playing enough tournaments and his untimely Jan. 5 split with coach Roger Rasheed sudden and rancorous, despite Rasheed's gracious public statement would derail anyone, besides, perhaps, the cantankerous and determined Hewitt. He still talks a good game and there's little reason to believe that wedlock and fatherhood have dulled his yearning to win his own Open. But if nothing else looks insurmountable to him then Federer might. Hewitt has lost his last nine meetings with the world No. 1 and collected only three sets in the process. For Hewitt to win the tournament, he probably needs someone else to get rid of Federer for him. As time passes, 2005 is looking like a fateful missed opportunity for the top-ranked Australian. Riding into the Melbourne final on a wave of momentum and national fervor, Hewitt succumbed to Safin even though the Russian was floundering for the first set and a half and ready to be put to sleep. He may never get as good a chance again. 7. Is any other Australian a hope? Um, no. In case you've missed it, Australian tennis is anchored in the Bay of Nowhere. After Hewitt, there's Chris Guccione (ranked 107, though with a bullet), Mark Philippoussis (122, injured again and out of the Open), then three guys around 160. One of these players, most likely the big-serving lefty Guccione, might string together a few wins in the first week to give locals something to get excited about, but anything beyond that would be astonishing. 8. Is there a bright spot for Australian tennis? Possibly: his name is Bernard Tomic and he'll be contesting the junior version of the Australian Open. From the Gold Coast, Tomic raised insiders' eyebrows last year by winning four ITF under-18 events as a 13-year-old. Apart from an impressive baseline game, Tomic, now 14, plays with the kind of palpable intensity that these days is a prerequisite for getting anywhere in tennis, and he looks destined to be a tall boy, perhaps 190-cm by the time he stops growing. The leap from juniors to the Tour is huge and the tennis canyon is full of former prodigies who didn't make it. But Tomic is the best Australian prospect since Hewitt. 9. What might be the effect of the Open using Hawk-Eye electronic line-calling technology for the first time? Happier players. As seen at last year's U.S. Open and numerous events since, this is the best innovation in tennis since yellow balls. As well as appealing to everyone's sense of justice, viewers no longer have to watch players fume and sulk like prima donnas when a close call goes against them. Fears that Hawk-Eye would hold up play excessively have proved unfounded: it's quick, reliable and altogether satisfying. 10. What about the women's event? Justine Henin-Hardenne's withdrawal throws this wide open. The women most likely are Amelie Mauresmo (France), Kim Clijsters (Belgium) or Maria Sharapova (Russia) in that order but watch out for Martina Hingis. A three-time winner between 1997-99 and now well into her comeback, Hingis' peerless touch and tennis instincts (the Agassi factor again) could help turn this year's Open into a Swiss parade.