Middlesbrough were left to rue a glut of missed opportunities, as they were held to a 0-0 draw by Southampton in the first leg of their Championship play-off semi-final.
Kim Hellberg's side were fuelled ahead of kick-off after Southampton were charged for allegedly spying on their opponents, but they were unable to find a way through at the Riverside Stadium.
Middlesbrough pinned Southampton back from the first whistle and saw their first big chance fall to Morgan Whittaker, who fired his left-footed attempt over the crossbar.
The hosts' dominance continued as Riley McGree skewed his effort agonisingly across goal after being brilliantly picked out by Callum Brittain's cross, before Luke Ayling's sighter had visiting goalkeeper Daniel Peretz worried.
But Middlesbrough's best chance of the half came 10 minutes before the break when Cyle Larin had his pocket pinched by McGree, with the midfielder feeding into Tommy Conway, who saw his curling first-time strike rattle the right post.
Southampton improved after the break and almost snatched the opening goal five minutes after the restart, but Larin was unable to trouble Sol Brynn with his back-post header.
The Saints then came close twice in quick succession when Taylor Harwood-Bellis' 84th-minute header struck the crossbar before substitute Samuel Edozie rolled his attempt just wide, as the scores ended level ahead of Tuesday's second leg.
Data Debrief: Pressure ramps up on misfiring Middlesbrough
Middlesbrough may live to regret not taking their chances during a one-sided first half that saw them register 17 shots, four of which were on target, while also restricting their opponents to no attempts at Brynn's net.
Boro finished with an expected goals (xG) total of 1.82 from their 21 attempts, compared to Southampton's 0.53 from their six shots, though Tonda Eckert may feel his team could have nicked a goal at the death.
In their six previous EFL play-off campaigns, Middlesbrough have won the first leg of their semi-final tie only once (D3 L2), winning 2-1 at Brentford in 2014-15, and they could be made to pay at St. Mary's next week.