WA went to stumps on day one at 8-325, with Whiteman (104 off 154 balls), Connolly (73no off 79 balls) and veteran D'Arcy Short (50 off 127 balls) the stars of the innings.
The Warriors pulled off two big selection calls leading into the match, handing Connolly his Shield debut and bringing in Short as a replacement for the injured Cameron Bancroft (concussion).
Short rode his luck on the way to posting the eighth half-century of his first-class career.
He was caught off a no-ball on 13 before being dropped on 16 by Caleb Jewell at first slip.
Put down at first slip! Tasmania still searching for their first wicket — cricket.com.au (@cricketcomau) #SheffieldShield pic.twitter.com/4v5x60cTaIMarch 21, 2024
Short's 110-run opening stand with Whiteman set the foundations for WA's innings.
WA lost their way in the middle part of the day, slumping from 2-193 to 5-215.
But Connolly showed nerves of steel to give WA's total a timely boost.
The 20-year-old became a cult hero a year ago when he led the Perth Scorchers to victory in the BBL final against Brisbane.
Connolly was set to play in the first Shield game of the current season, but those plans were scuppered when he broke a toe while jumping off a boat.
He made up for lost time on Thursday.
Connolly's first 32 runs were all boundaries, and he reached his maiden Shield half-century off just 48 balls, featuring eight fours and two sixes.
He ended the day with 10 fours and three sixes to his name, and has the chance to post a dream century when play resumes on Friday.
Earlier in the day it was Whiteman in the spotlight as he brought up the 15th century of his first-class career.
Something special was required to bring Whiteman undone and Iain Carlisle came up with the goods by producing a delivery that jagged back an incredible amount to trap the WA skipper lbw.
Cameron Bancroft at the WACA Ground supporting WA - but getting no sympathy from his teammate Andrew Tye! � — cricket.com.au (@cricketcomau) #SheffieldShield pic.twitter.com/6vGBxAhndzMarch 21, 2024
WA's bid to win a "three-peat" of Shield titles was dealt a huge blow on Sunday when star opener Bancroft crashed his bike.
A banged-up Bancroft spent a night in hospital and was ruled out of the final, but he came along on Thursday to support his teammates.
Tasmania are aiming to win their first Shield title since 2012/13.
