Aitor Karanka’s team continued their good run of form, as they defeated their Championship rivals Wolves 3-0 at the Riverside Stadium in the third round of the League Cup.
Boro went ahead in the 37th minute when Albert Adomah found the target after De Pena's cross caused panic in the Wolves defence.
Diego Fabbrini doubled the hosts' advantage in the 57th minute, and seven minutes later Adomah put the game beyond doubt with his second goal of the evening.
De Pena, who joined Middlesbrough from Nacional in the summer transfer window, was delighted with his team’s victory in the League Cup.
The 23-year-old winger was also happy to have made a telling contribution on his debut for the Championship club.