Boro have ascended the second-tier table after the appointment of Michael Carrick as manager, whereas Brighton continue to develop as a side despite the departure of ex-boss Graham Potter and many key players in the summer.
Match preview
After starting the Championship season with just one win from seven matches under Chris Wilder, Middlesbrough found themselves trapped in the relegation zone, with their hopes of reaching the playoffs this campaign quickly fading.
That poor run of form prompted the Boro hierarchy to dispose of Wilder and recruit ex-Manchester United player Carrick, with the club now reaping the rewards of that decision a few months ago.
Middlesbrough have lost just twice in 10 matches under the stewardship of Carrick - a run which includes seven wins and the resurgence of attacking talent such as Chuba Akpom and Matt Crooks.
Boro's 3-1 success over Birmingham City on Monday meant they climbed to fifth in the second-tier standings as league matters pause briefly for a weekend of FA Cup action, a remarkable achievement by a 41-year-old manager undertaking his first-permanent coaching role.
Fans at the Riverside Stadium were treated to a brilliant FA cup journey last campaign as their side reached the quarter-finals, beating Mansfield Town, Manchester United and Tottenham Hotspur before falling to Chelsea in the last eight.
On Saturday Brighton will be hoping to make amends for a poor performance in England's other major cup competition, as they allowed League One's Charlton Athletic into the Carabao Cup quarter-finals after a penalty-shootout defeat at The Valley.
For a club that has never lifted a major trophy that defeat to the Addicks was particularly painful, although they have not allowed that loss to derail a productive season in the Premier League.
The Seagulls currently sit eighth in the top flight after an impressive 4-1 victory against Everton at Goodison Park - a second away game in succession that Roberto De Zerbi's men have blown away their opposition.
The departures of star players such as Yves Bissouma, Ben White and Marc Cucurella in recent seasons have threatened to kill the momentum in East Sussex, but the club have always found a way to recruit capable replacements and new talent to ensure the continued progression of the team.
Two perfect examples of that process in motion are Kaoru Mitoma and 18-year-old Evan Ferguson, with both netting on Merseyside against Everton alongside Pascal Gross and Solly March.
Brighton have reached the FA Cup final on one occasion in their history, losing to Manchester United in a replay during the 1982-83 season after drawing the initial game 2-2 at Wembley Stadium.
Middlesbrough form (all competitions):
W
W
L
W
W
W
Brighton & Hove Albion form (all competitions):
L
D
L
W
L
W
Team News
Middlesbrough will be without defender Matthew Clarke for the visit of Brighton with the 26-year-old suffering from a back injury, meaning Darragh Lenihan and Dael Fry are likely to continue as the centre-back partnership.
Akpom and Crooks have been in blistering form of late for Boro, but if Carrick opts to rotate his XI for this cup clash then the likes of Rodrigo Muniz and Duncan Watmore are candidates for starting berths on Saturday.
Boro look set to bring in Cameron Archer from Aston Villa this January, although the 21-year-old is unlikely to be signed in time to make an appearance in this fixture.
Brighton's World Cup winner Alexis Mac Allister featured off the bench in the victory over Everton and could be handed his first start since returning from the wild celebrations in Argentina.
Danny Welbeck and Adam Webster are both doubts for Saturday's trip to the Riverside, whereas Poland's Jakub Moder is out until at least next month due to a ligament injury.
Middlesbrough possible starting lineup:
Steffen; Smith, Fry, Lenihan, Giles; Howson, Hackney, Forss, Akpom, McGree; Crooks
Brighton & Hove Albion possible starting lineup:
Steele; Lamptey, Dunk, Colwill, Estupinan; Gilmour, Gross, Lallana, Mac Allister, Trossard; Ferguson
We say: Middlesbrough 1-2 Brighton & Hove Albion
Middlesbrough are flying in the Championship under Carrick and should fancy their chances against the Premier League visitors on Saturday, especially considering their run in the FA Cup last season.