Both Thirimanne, who scored a career best 91 just three days after joining the Sri Lanka squad as an emergency replacement, and Jayawardene, who hit 72 in his penultimate innings as captain, threatened to make a sunny day in Sydney their own.
Ultimately though, Australia captain Michael Clarke's decision on winning the toss to send his pacemen out to bowl first was all but vindicated and the hosts will have finished the day confident they can wrap up the series 3-0.
Jackson Bird, the least experienced of the quartet, took 4-41, Mitchell Starc 3-71 and Peter Siddle grabbed a brace with spinner Nathan Lyon pitching in to end Thirimanne's knock just shy of his maiden test century.
Brought in for his first test since last April to replace the injured Kumar Sangakkara, Thirimanne had shown a fight that had largely been absent from the batting of his better-known compatriots on the tour so far.
The 23-year-old lefthander survived an lbw decision on his first ball courtesy of the television appeal and assumed the mantle from Jayawardene when his captain was dismissed after his first half century outside Sri Lanka for more than three years.
Thirimanne reached his second half century with a cover drive off Mitchell Johnson for three runs and, punishing any loose deliveries, smashed 13 fours and a six in his 151-ball knock.
The end to his innings came chasing another boundary off Lyon and it took an exceptional catch from David Warner at cover point to snare the miscued drive, leaving the batsmen bowed over his bat in despair.
Injuries had forced Jayawardene into naming a team with four changes from the side that was thrashed by an innings and 201 runs in Melbourne last week and he seemed determined to make up for that humiliation, on his own if necessary.
After a cautious start, the 35-year-old came out firing after lunch and smashed 13 boundaries in his 154-minute knock before Starc removed him with a fizzing ball that caught a thick edge and flew to Clarke in the slips.
There was a nervous wait for the raucous crowd basking in the sun at the Sydney Cricket Ground while a check was made for the no ball, but the television pictures confirmed that Starc's heel had grazed the white line.
Starc, rested for the Melbourne test, also accounted for captain-elect Angelo Mathews (15) and returned to remove Dinesh Chandimal for 24 with a perfect yorker on the first delivery with the second new ball.
Bird had removed both Sri Lanka openers in the opening session, having Dimuth Karunaratne caught off a top edge for five and returning an hour later to dismiss Tillakaratne Dilshan, caught behind for 34.
His third victim was Rangana Herath (5) and, with the end of the day approaching, he returned to remove Suranga Lakmal (5) to end the Sri Lankan innings.
Michael Hussey, playing in his final test before retirement, got a huge cheer when he was handed the ball for two overs before tea but he was unable to snare what would have been a popular wicket to add to his three catches.
Former England captain Tony Greig, a popular media pundit in his adopted country who died last week, was remembered by the placing of a broad-brimmed hat on one set of stumps before the start of play.