In another semi-final, Telugu Titans, who finished second in the league table behind U Mumba, will cross swords with Bengaluru Bulls, who seem to hold a slight edge, having won both their league clashes against their Hyderabad rivals.
U Mumba, who lost just two games in the league phase of the tournament, have a well-balanced outfit spearheaded by their best player and captain Anup Kumar.
"Patna Pirates is a good team with a number of young players. It will be a tough game. We have a good team and we will try our best to win the trophy. I will be very disappointed if we don't go on to clinch the title," said the India international and Incheon Asian Games gold medallist.
Kumar said defence has emerged a key factor in this edition of Pro Kabaddi League.
"All the teams are tightening their defence," said Kumar, who has collected 2400 points in the league stage, including 219 raid points and 21 while defending.
Pirates' captain Sandeep Narwal promised their defence would hold up and tame the high-flying Mumbai side.
"We are determined to do well in defence. Tomorrow we will be defending with all our might against Mumbai and I would also concentrate a lot on defence," said Narwal, who was made captain after India captain Rakesh Kumar picked up an injury early on and could not continue.
Pirates, who finished fourth in the league with seven wins and six losses for a grand tally of 41 points, would also be missing Ravi Dalal, who, too, is on the injured list.