Holder of 12 world titles, Advani had a minor blip as he lost two frames but he held his composure en-route to a 4-2 win over Siddharth Parikh of Railways.
Leading 2-0, the 29-year-old was stunned in the third frame when Parikh posted a 107 break on the way to a 114-150 win, but Advani bounced back winning the fourth to make it 3-1.
Advani lost the fifth frame narrowly but returned stronger to clinch the issue in the sixth.
The second semifinal went to the deciding seventh frame, as Mumbai lad Sitwala faced a stiff resistance from B Bhaskar of Tamil Nadu.
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It was a neck-and-neck tussle with Bhaskar playing the catching up game and holding Sitwala every time he took a lead. The two were locked 3-3 to take the contest to the deciding seventh frame.
Trailing 20-127 in the decider, the Petroleum Sports Promotion Board employee held his nerve as he posted a break of 127 to post a nerve-wracking 4-3 victory.
For Sitwala, this will be his third national final after his appearances in 2006 and 2003, losing on both occasions.
Sitwala said he's not fancying his chances against Advani and would rather focus on improving his game.
"If I gave 75 per cent today I will have to give at least 95 per cent to stand a chance against him (Advani)," he said.
Sitwala would look to take inspiration from his win against Advani in the 2010 World Championship on his way to the final.