Durban - The Waratahs have vowed to batter the Stormers' iron-clad defence with strong ball-running and physical play at the breakdown in this Saturday's Super 14 semi-final at Newlands.The match represents a huge challenge for the Waratahs against a second-placed side that boasts the best defence this season, having leaked a miserly 171 points. But NSW No 8 Ben Mowen insists the Waratahs, who conceded the second fewest points (288), can infiltrate the Stormers' defence in front of a parochial Cape Town crowd.''I am 100 percent certain we can,'' Mowen said. ''When we played them in round two … the feeling after that game was very similar to the Highlanders [loss], where we felt coming off the park that we hadn't played any of our footy and really hadn't been physical enough.''[The] lesson is how hard you have to be in the physical contest, particularly against the South African sides.''Mowen, who played at No 6 when the Waratahs lost to the Stormers but has been at No 8 since Wallabies enforcer Wycliff Palu was sidelined for the season with a knee injury, says the Stormers ''are a team built around strong defence, and try to create opportunities to attack from their defence''.Asked how the Waratahs could penetrate such defence, he said: ''It all comes down to the ball carry and how physical you are at that first breakdown. It will be all based on getting on that front foot early off set pieces and getting momentum so they don't get a chance to set their defence and get off the line.''Teams that have had success against them have created quick ball and forced the defence to be on their heels. It allows you to play a natural game.''The Stormers, however, believe the Waratahs will adopt a different tactic when attempting to breach the hosts' defence, which has allowed just 17 tries from 13 games this season.''If you can't go around or through a team, then I suppose there is only one more alternative, you have to go over,'' Stormers coach Allister Coetzee told the www.keo.za website.''The Cheetahs tried [a kicking game] when they came to Newlands, and the Brumbies enjoyed some success through the kicking game of Matt Giteau. The Waratahs have some great kickers in Berrick Barnes, Kurtley Beale and even Drew Mitchell, and we are wary of their abilities with the boot.''Coetzee is expected to keep faith in the halves combination of Dewaldt Duvenage and Peter Grant, even though Ricky Januarie was the Stormers starting halfback when they beat the Waratahs in round two.''Dewwies has really stood up and the tackle count will verify my statement,'' Coetzee said. ''I don't want to make unforced changes at this stage but I have to say I'm happy with Dewwies' defence. He's not only made a lot of tackles but the kind of positive hits that drive attacking players back. He'll certainly take that momentum into the semi-final.''The Waratahs, meanwhile, have spent much of their time studying the game plans of the four teams to have defeated the Stormers this season.''If teams have explored that part of their game and have had success, then it is something we will definitely go back and look at,'' Mowen said.The Waratahs will name an unchanged line-up from that which triumphed over the Hurricanes in Sydney last Friday. Reserve hooker Damien Fitzpatrick passed a fitness test on his injured knee, while Dan Palmer has recovered from a head knock, although he must pass two more checks before game day.