Match ends, Middlesbrough 0, Brighton and Hove Albion 0.
Middlesbrough dropped to fourth in the Championship as they were held to a goalless draw by Brighton.
Brighton's Chris O'Grady spurned the best chance of an uneventful match when he turned Greg Halford's cross over from six yards.
The result means Middlesbrough will travel to Brentford in the play-off semi-final first leg on Friday 8 May at 19:45 BST.
Brighton, who had little to play for, finish the season in 20th place.
The dour draw ended Middlesbrough's six-match winning home streak in front of a crowd of 33,381 - the biggest of the season at the Riverside Stadium.
Chris Hughton's visitors enjoyed the better of the early stages but both Gordon Greer and Lewis Dunk fluffed their lines in front of goal after deliveries from Dale Stephens set-pieces.
Boro wasted their best chance of the first half when left-back Fernando Amorebieta stole possession from Joe Bennett on the half-way line and charged at Brighton before pulling back to Kike.
But the Spaniard's first touch took him away from goal and the Seagulls were able to clear.
Brighton should have taken the lead with 20 minutes to go when former Sunderland defender Halford broke down the wing and crossed into the box but O'Grady blazed over the bar from close range.
Kike was guilty of another missed opportunity in the closing stages when a loose ball fell kindly to him in the area but he but scuffed his shot wide.
Middlesbrough manager Aitor Karanka: "It's not important who we play against in the play-offs, but we need to improve because the last few performances weren't good.
"We were expecting an amazing game with the fans behind us. We have another game at home to thank our fans for this season. We have to prepare as well as we can.
"It's been an amazing season and we can't forget now we have to prepare well and be more together than ever to go into the play-offs in a positive way. Promotion is in our hands."
Brighton manager Chris Hughton: "We were desperate to give a good account of ourselves.
"I wanted the game to mean as much to us as it did to Boro. As an away side, we did really well. We could have nicked it with a couple of late chances, and it looked like it would be one individual flash of brilliance that would win it.
"Overall a draw was a fair result and I was pleased to finish the season on a positive."
- 32TiendalliBooked at 34minsSubstituted forNsueat 59'minutes
- 34ForshawSubstituted forVossenat 59'minutes
- 10TomlinSubstituted forReachat 73'minutes
- 24InceSubstituted forCalderonat 79'minutes
- 18Forster-CaskeyBooked at 87minsSubstituted forTilleyat 90+5'minutes
- 11O'GradySubstituted forMackail-Smithat 72'minutes
- 25Lua Lua
- Andy Madley
- Shots on Target
Second Half ends, Middlesbrough 0, Brighton and Hove Albion 0.
Substitution, Brighton and Hove Albion. James Tilley replaces Jake Forster-Caskey.
Attempt saved. Íñigo Calderón (Brighton and Hove Albion) right footed shot from outside the box is saved in the bottom left corner. Assisted by Craig Mackail-Smith.
Corner, Middlesbrough. Conceded by Joe Bennett.
Attempt missed. Kike (Middlesbrough) right footed shot from the centre of the box misses to the left. Assisted by Albert Adomah with a cross.
Foul by Íñigo Calderón (Brighton and Hove Albion).
Daniel Ayala (Middlesbrough) wins a free kick in the defensive half.
Attempt missed. Jelle Vossen (Middlesbrough) right footed shot from outside the box is close, but misses to the right. Assisted by Adam Clayton.
Jake Forster-Caskey (Brighton and Hove Albion) is shown the yellow card for a bad foul.
Foul by Jake Forster-Caskey (Brighton and Hove Albion).
Albert Adomah (Middlesbrough) wins a free kick on the right wing.
Attempt blocked. Íñigo Calderón (Brighton and Hove Albion) right footed shot from outside the box is blocked. Assisted by Dale Stephens.
Attempt saved. Kike (Middlesbrough) right footed shot from the centre of the box is saved in the centre of the goal. Assisted by Emilio Nsue Lopez with a cross.
Substitution, Brighton and Hove Albion. Íñigo Calderón replaces Rohan Ince.
Craig Mackail-Smith (Brighton and Hove Albion) wins a free kick on the right wing.
Foul by Fernando Amorebieta (Middlesbrough).
Gordon Greer (Brighton and Hove Albion) wins a free kick in the defensive half.
Foul by Kike (Middlesbrough).
Delay over. They are ready to continue.