Colombo, June 28 : Former Aussie cricketer Shane Watson believes that spin bowling, and veteran off-spinner Nathan Lyon specifically, will be the key to Australia beating Sri Lanka in the upcoming two-match Test series, starting on June 29. Both Test matches will be played in Galle -- traditionally a spinners' paradise -- and Watson said it was a no-brainer for Australia to play at least a two-man spin attack. "Australia again will have to take in two spinners, for sure and the batters will have to bat very well in the first innings because it can be very challenging to bat in the second innings when the wickets start to dry and the footmarks come into play," Watson told Isa Guha in the latest episode of The ICC Review. "The Test series that I played over there, quite a few years ago now, definitely used a drier sort of wicket that does turn quite a bit," he added. According to Watson, Lyon (427 wickets in 108 matches) and Mitchell Swepson, who debuted in Pakistan recently and impressed everyone, must have an impact for top-of-the-table Australia to maintain their momentum in the ICC World Test Championship standings. "The spinners will have to bowl really well. Nathan Lyon's going to have to step up and be the man to help Australia win those Test matches and bowl Sri Lanka out. It's going to be a big test for Mitchell Swepson, who played the last couple of Tests in Pakistan. It potentially could be a make-or-break Test series for him. If he's able to bowl really well, then he could lock himself into being No 2 for quite a while. But if things don't go exactly right, then Australia might start to look for someone else," he said. "All reports suggest that Mitchell has been bowling really well, taking a lot of wickets in Shield cricket as well. So there are great signs. Hopefully, he's able to step up as well because he's going to be really important," he added. Notably, 'spin' was not a major factor during Australia's 1-0 series victory in Pakistan but Watson believes Australia batters will face a sterner slow-bowling assignment in Sri Lanka. "They will be tested more because the ball's going to turn a lot more than what we saw in Pakistan. The ball didn't turn a lot and it was more the reverse swing that was the big weapon in that series. So it's going to really test the ability of Australia's batsmen to play against spin," the former star all-rounder said. Despite it once being considered a wea'ness in Australia's batting line-ups, the former Australian cricketer suggests that it's now a strength. "Usman Khawaja is as good a player of spin as we've got in Australia. Dave Warner, he's experienced and knows how to play spin. Marnus (Labuschagne), one of his strengths is playing spin. Steve SmithÂ? so that the top four alone, their ability to play spin in all spinning conditions is as good as there really is in the world at the moment," Watson said. "It will be a great test to see where their skills are at right now and I'd be surprised if they didn't make the most of the first innings, even if the ball is turning quite a bit because they are highly-skilled batsmen," he concluded. /IANS