A final friendly against Real Betis has been added to Boro's first team fixtures for pre-season.
National League side Chesterfield will play host as the Teessiders take on the La Liga outfit on Saturday 22 July (kick-off 2pm).
Real Betis, managed by Manuel Pellegrini, finished sixth in the Spanish top flight last season and will present a welcome challenge for Michael Carrick's side.
Boro are in Portugal this week as pre-season preparations are taken up a notch in the Algarve heat.
Friendlies against Hartlepool United, York City, Rotherham United and now Betis follow, before a trip to Bradford City and a Riverside match-up with Auxerre in the final week before the new season proper.