A flat surface had been expected at Karachi. Instead the first day delivered 13 wickets, eight of them in a manic final session, as Pakistan first nosedived to 191 all out, losing their last six for 24 runs, before Sri Lanka limped their way to 64 for 3 at the close.
The day belonged to all manner of bowlers - speedsters, seam-bowling wizards, ambling spinners - but if one stood out from the crowd, it was Sri Lanka's Lahiru Kumara. He touched 150kph at times in the morning, and kept his pace up all day, sending down hostile bouncers in stretches, and teasing the outside edge at other times. He had most success going full, straight and fast, however, nailing Abid Ali and Yasir Shah lbw, and cleaning up Mohammad Rizwan with an inducker on his way to 4 for 49 from 18 overs.
Lasith Embuldeniya, the left-arm spinnner, was the perfect foil, recovering from a wayward first session to settle into an alluring rhythm later on. He had excellent drift from the outset, but once he'd settled into his work after lunch, he had flight, dip, bounce and spin at his command as well. He took the vital wicket of Babar Azam early in the second session, getting one to spit past the face of his bat as he ran down the pitch at him, Niroshan Dickwella completing an easy stumping. Just before that middle session finished, Embuldeniya also trapped Haris Sohail in front of the stumps with another sharply-turning delivery. Taking two tail-end wickets as well, he finished with 4 for 71.
Their middle and lower orders having collapsed abysmally either side of tea, Pakistan's bowlers were then called upon to haul their side back into the game. Hunting as a pack in the dying light, Shaheen Afridi and Naseem Shah both delivered searing pace - Naseem the quicker of the two, frequently breaching the 145kph mark. Shaheen made the first breakthrough, nicking off Oshada Fernando in the seventh over with a full delivery outside off stump that prompted a fatal drive.
Mohammad Abbas had perhaps been a little underwhelming in his first spell, sharing the new ball with Shaheen, but was at his conniving best in the second. He angled one across Dimuth Karunaratne before jagging it back off the seam - Karunaratne managing only to drag the ball back onto his stumps after attempting to cut. Abbas' next dismissal - the one to round off the day - was superbly characteristic of his best bowling. He sent a length ball just outside off stump at Kusal Mendis, who is especially vulnerable in that area, wobbled it away, and drew an outside edge that flew low to second slip.
Barely 90 minutes previous, Pakistan had been reeling, after their sudden surrender with the bat. By the end of the day, they could see a path back into this game.
The collapse had been partially the result of good Sri Lanka bowling, but perhaps it did not need to be quite so dramatic. Pakistan had seemed to be building a decent score, at 167 for 4, when Haris was nailed in front by Embuldeniya. Then first thing after tea, Kumara delivered the over of the day to really set Pakistan's decline in motion.
He sneaked a ball between bat and pad to rattle Rizwan's stumps, then next ball hit Yasir Shah on the boot to effect a plumb lbw. Sri Lanka would lose a review trying for a third wicket a few balls later, but Kumara nevertheless completed a double-wicket maiden that transformed the outlook of the game. From then on, it was a question of how many Asad Shafiq would manage to squeeze out in the company of the tail. It would turn out it wasn't many.
Shafiq, who made 63, was day one's top scorer, and was the only other half-centurion after Babar had lit up the morning with 60 off 96 balls. Through those early sessions, Pakistan's batsmen looked largely comfortable, and there didn't seem to be much to fear from the surface. Babar drove majestically as usual, and ran down the pitch once to clobber Embuldeniya over long on for six. His dismissal was almost certainly the result of telegraphing another advance against Embuldeniya, who saw the batsman coming and slipped in a shorter ball that spun.
When Sri Lanka's third wicket fell with about 15 minutes to go till stumps, Embuldeniya came out as the nightwatchman. He will have Angelo Mathews for company when play resumes on day two.
Sri Lanka 64 for 3 (Abbas 2-21) trail Pakistan 191 (Shafiq 63, Babar 60, Kumara 4-49, Embuldeniya 4-71, Vishwa 2-31) by 127 runs