The White Rose, celebrating their 150th anniversary this season, were already trailing Sussex by eight runs on the first innings at stumps after being skittled for 96.
Sussex's batsmen ensured a miserable day for the hosts as they reached a premature close at 104 for three, with Chris Nash's 80 proving the Headingley wicket was not the minefield Yorkshire's card suggested.
On the eve of the season skipper Andrew Gale suggested his newly-promoted side had designs on marking their historic year by winning the title - but already those claims seem over ambitious.
After being sent in just three Yorkshire batsman managed double figures as 24-year-old right-armer Chris Jordan (six wickets for 48 runs) served a reminder of the step up in class to the top tier.
Opener Nash then almost surpassed Yorkshire's meagre total on his own before he became the third of veteran Ryan Sidebottom's three wickets, caught behind by Jonny Bairstow, to at least offer the hosts some comfort.
Warwickshire's title defence got off to a solid start as they bowled out newcomers Derbyshire for 226 at Edgbaston. The Bears were without frontline seamers Keith Barker, Chris Woakes and Boyd Rankin but Chris Wright and Jeetan Patel filled the void with three wickets apiece.
It could have been worse for Derbyshire but Tony Palladino's late 68 edged them to a first point of the campaign, before Warwickshire closed at 14 without loss.
Middlesex seamer Toby Roland-Jones cashed in most on the early-season bowler-friendly conditions with a career-best haul of six for 63 to help bowl out Nottinghamshire for 278. Australia opener Ed Cowan top-scored on his debut for the hosts with 61 while James Taylor, left out of England's performance squad for the summer, was next best with 55.
Dan Housego and Hamish Marshall batted their way into the record books as Gloucestershire reached 300 for three in their opening County Championship Division Two match against Essex at Chelmsford.
Both scored centuries during which they broke the previous highest fourth-wicket partnership record for Gloucestershire in matches against Essex which had stood for 106 years.
They have so far put on 229 runs, beating the 153 stand featuring Gilbert Jessop and Tom Langdon at Leyton in 1907.
Housego will resume on day two on 124, a career-best score, while Marshall will seek to add to his 120.
Northamptonshire took full control against Glamorgan in Cardiff after bowling out the hosts for 134.
Steven Crook claimed four wickets and captain Stephen Peters then cracked a half-century to help his side to 108 for three - a deficit of 22 runs.
Worcestershire just about held the upper hand after the opening day of their battle against fellow relegated rivals Lancashire at Old Trafford.
Moeen Ali's 78 from 188 balls ensured the Pears laid a solid foundation of 227 for six.
Hampshire recovered from losing both openers before they had scored to be 286 for four against Leicestershire at Southampton.
Jimmy Adams and Michael Carberry both failed to trouble the scorers before Australia Twenty20 captain George Bailey fell seven short of a debut century to lead the recovery. James Vince (77) and Sean Ervine (57) built on Bailey's good work in an unbeaten stand of 136 for the fifth wicket.
Middlesex were 12 without loss in reply, while Ben Stokes hit 49 to lead a Durham recovery from 94 for five to 250 all out at Chester-le-Street. Peter Trego and Steve Kirby shared three wickets apiece for Somerset.
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