Williams has won 10 of the 11 matches she's contested so far this year, losing only to Angelique Kerber in the Australian Open final. Excluding withdrawals and retirements midway through an event, the American hasn't failed to reach the semifinals of a tournament since Wimbledon 2014.
The world number one hasn't dropped a set in this tournament, beating the defending champion and fifth seeded Simona Halep 6-4, 6-3 in a high quality, raucously supported quarterfinal.
Radwanska is into her eighth semifinal in her last nine tournaments, winning Shenzhen and losing in the semifinals of the Australian Open and Doha this year. Despite heavy losses to Williams and Carla Suarez Navarro in these events, the Pole will deservedly take the number two spot in the world rankings next week.
After saving a match point to beat Dominika Cibulkova in the second round, the current world number three hasn't looked back, at best accounting for the world number nine and eighth seed Petra Kvitova 6-2, 7-6 (3) in the quarterfinals.
A winner of 21 Grand Slam singles titles, Williams is no stranger to winning big. Looking for her 70th title this week, the 34-year-old has won this event twice in the past back in 1999 and 2001. In fact, she has only suffered one main draw defeat at Indian Wells, losing to Mary Pierce in the quarterfinals back in 2000. That being said, Williams boycotted the event for 14 years due to the controversy surrounding her victory in 2001, only returning last year to reach the semifinals before a knee injury forced her to withdraw.
Since Tokyo last September, Radwanska has won four of her 18 career titles, including her biggest to date at the WTA Finals in Singapore. Always at home in the desert, the recently turned 27-year-old has reached the fourth round or better eight times in 10 visits, at best reaching the final in 2014 where injury hampered her in a loss to Flavia Pennetta. Regardless of the outcome of this match, her result this week is already a marked improvement on her third round exit against Heather Watson last year.
Williams dominates their head-to-head 9-0 and crushed Radwanska 6-0, 6-4 in their most recent meeting at the Australian Open. At best, the Pole won a set in the 2012 Wimbledon final, recovering from 2-4 down in the second to push the match to a third before losing 6-1, 5-7, 6-2.
The American serves too strongly for Radwanska and always has a chance on the return. In six previous hard court meetings, Williams has only dropped more than six games once (Toronto 2013) as she has time to set up her shots, moving forwards to dispatch defensive lobs with drive volleys.
As she did against Kvitova, Radwanska must look to mix things up against Williams. Though it's not wise to drop shot the extremely fast top seed, the Pole must use the slice and off pace shots to try and disrupt the American's rhythm on this slow hard court, as did Roberta Vinci at last year's US Open. All too often, Radwanska erroneously tries to live with Williams from the back court, which is something she can't afford to do. As Belinda Bencic and Angelique Kerber have proven recently, the world number one can be beaten with steady baseline play but a high first serve percentage and a willingness to take the ball on wherever possible is required.
Prediction: Serena Williams in straight sets