Boro finished fourth in the Championship last season, losing to Coventry City in the semi-finals of the playoffs, while Vitoria secured sixth position in Portugal's top flight.
Match preview
Vitoria claimed sixth in the Primeira Liga last season, picking up 53 points from their 34 matches, which has seen them qualify for the Europa Conference League second qualifying round.
Moreno's side will take on Slovenian outfit Celje for a position in the next round of the European competition, with the first leg of their contest set to take place on July 26 before the return match one week later.
Vitoria will also be in Taca da Liga second-round action against either Santa Clara or Tondela on July 28, while their league campaign begins away to Estrela on August 12, so competitive action is just around the corner.
The Portuguese outfit have a busy run of matches before then, though, facing Middlesbrough and Wolverhampton Wanderers on Saturday and Sunday respectively, while they will also take on Fafe, Rio Ave and Boavista in non-competitive fixtures.
Moreno's team have already been busy in the market this summer, bringing in Ze Carlos, Telmo Arcanjo, Joao Mendes, Charles and Ricardo Mangas to boost their squad for the new season.
Middlesbrough, meanwhile, enjoyed an excellent campaign under impressive head coach Michael Carrick, who lead the team to a fourth-place finish in the second tier following his arrival last October.
Boro therefore competed in the Championship playoffs, but they suffered a 1-0 defeat to Coventry, who were then beaten by Luton Town in the final at Wembley.
Middlesbrough are facing Vitoria as part of their training camp in Portugal, while they will also take on Hartlepool United, York City, Rotherham United, Real Betis, Bradford City and Auxerre in friendlies this summer.
Carrick's team will begin their 2023-24 Championship campaign at home to Millwall on August 5 and will then be back in action three days later against Huddersfield Town in the EFL Cup.
Boro have only made one signing thus far this summer, bringing in Alex Gilbert from Brentford, but Rav van den Berg is said to be on the verge of joining from PEC Zwolle, while Sammy Silvera and Tom Glover are also believed to be closing in on moves to the Riverside Stadium.
Team News
Vitoria could have five debutants in Saturday's behind-closed-doors friendly, with Ze Carlos, Arcanjo, Mendes, Charles and Mangas all pushing to be involved at some stage.
The Portuguese outfit also have a number of players back at the club following loan spells last season, with Falaye Sacko among those likely to be given a chance to impress.
Andre Silva is set to start in the final third of the field for the home side, while Jorge Fernandes and Matheus Indio should also be involved at some stage of the contest.
Middlesbrough will be unable to call upon either Chuba Akpom or Matthew Hoppe for this contest, as neither player made the trip to Portugal due to minor injury problems.
However, Carrick does have a strong squad available, and there are also set to be opportunities for youngsters in the shape of Sonny Finch, Jack Stott and Nathan Fisher.
Gilbert has also linked up with the squad in Portugal and is set for his debut, while Josh Coburn and Marcus Forss could both be in the starting side for the Championship outfit.
Vitoria de Guimaraes possible starting lineup:
Charles; Ze Carlos, Bamba, Fernandes, Freitas; Handel, Manu, Indio; T Silva, A Silva, Safira
Middlesbrough possible starting lineup:
Roberts; Smith, McNair, Lenihan, Dijksteel; Hackney, Fry; Forss, Barlaser, McGree; Coburn
We say: Vitoria de Guimaraes 1-1 Middlesbrough
Carrick will want a tough test at the start of pre-season, and Vitoria are a classy outfit, so it should be a close match on Saturday afternoon. It is always difficult to know exactly what to expect from friendlies at this stage of the summer, but we are predicting that the spoils will be shared in this contest.