Karnataka 202 (Uthappa 68, Nair 49*, Thakur 4-61) and 10 for 2 lead Mumbai 44 (Vinay Kumar 6-20) by 168 runs

Twenty-one wickets fell on the opening day of the first semi-final, as hosts Karnataka gained an upper hand against Mumbai at the Chinnaswamy Stadium. If Mumbai's bowlers - led by Shardul Thakur's four-wicket burst - did well to bowl the defending champions out for 202, the hosts bounced back strongly by winding up Mumbai for a paltry 44. The visitors then dismissed openers Robin Uthappa and KL Rahul for the second time in the day, but were left facing an uphill task going into day two.

The scoreboard may give an impression that the greenish Chinnaswamy track was unplayable. However, the track, with a bit of cracks, wasn't bad at all. The day was highlighted by a combination of good bowling, lack of application from most batsmen, mediocre running between the wickets from Karnataka, and atrocious umpiring from Vineet Kulkarni.

Karnataka chose to bat, knowing it would be difficult to bat in the fourth innings. Rahul started by playing attacking shots right from the off, but he miscued a pull off Thakur to hole out to Balwinder Singh Sandhu at deep fine-leg in the fifth over. Soon after, R Samarth, coming into the match on the back of two big hundreds, backed up too much at the non-striker's end. Uthappa sent him back, but even a desperate dive fell short as Akhil Herwadkar found the target running in at point.

In the same over, Thakur trapped Uthappa plumb in front with a fuller delivery. But to the utter shock of everyone at the ground, Kulkarni turned the appeal down, possibly due to Uthappa falling over in his follow-through. The leading run-scorer of the season was on 12 then, and punished Mumbai with his stroke-play. Every time Mumbai gave Uthappa width, he made use of it by hitting through the gap.

Four overs before the scheduled lunch break, however, Uthappa was left in two minds and eventually ended up edging one from Wilkin Mota that moved away to Suryakumar Yadav at wide slip. After the break, the Mumbai seamers corrected their lines and bowled much tighter to reap rich rewards.

Had Yadav not dropped Karun Nair off Mota when the batsman was on 8, Mumbai could have well restricted Karnataka for a sub-150 total. But Nair remained unbeaten, scoring 49 till he eventually ran out of partners. The pace quarter's immaculate line and lengths were rewarded consistently, and Vinay Kumar's unnecessary run-out didn't help Karnataka either.

The Karnataka innings got over in the extended second session. But the Mumbai batsmen made Karnataka's batting effort appear stupendous. Herwadkar tried to play the second ball of the innings across, missed it and opened the floodgates by giving Vinay the first of his six wickets.

Vinay and Abhimanyu Mithun pitched the ball in the perfect channel and Mumbai batsmen continued to make mistakes consistently. Only two batsmen - Shreyas Iyer, who played across to be trapped in front of the wickets off Mithun, and Suryakumar Yadav,who was the last man out - could make double-digit scores.

Mumbai captain Aditya Tare was at the receiving end of Kulkarni's second howler when Vinay pitched one wide and Tare tried to slash it. The ball moved after missing the edge, but Kulkarni upheld the appeal. The next ball, Siddhesh Lad gave catching practice to Shreyas Gopal in short midwicket.

Twice during his six-wicket haul was Vinay in with a chance to register a hat-trick. Nikhil Patil and Shardul Thakur prevented Vinay from achieving the feat, but both the batsmen perished in the Karnataka captain's next over.

The Mumbai batsmen continued to succumb to the Karnataka pacers' onslaught, and folded in 77 minutes. The visitors had already been dealt a blow earlier as Abhishek Nayar was unavailable to bat. The allrounder had fallen awkwardly on his head while attempting to stop the ball in his follow-through during the second session and had to be taken to a hospital.

Mumbai showed great character last week by pulling things back in the second innings after faltering in the first against Delhi. It would require a humongous effort if they are to repeat the heroics this time around.

Amol Karhadkar is a correspondent at ESPNcricinfo