He came to Serbia in December 2010 and signed a loan deal with Red Star Belgrade after being recommended to the club by their former player Dejan Petković. Using Serbian transliteration his name is written as Kristijan Borha (Кристијан Борха) .
On 11 April 2012 he scored a goal in the derby against Partizan after coming on from the bench. This was Borja's first goal in a derby, meanwhile Red Star went through after winning both Cup matches 2–0 and 0–2.
Cristian Borja completed the rout in the 96th minute when he ran onto Diego Valdes' perfectly weighted pass and slotted a first-time effort into the far corner ... Enditem .