The 21-year-old, who is from the Czech Republic, got through the full 90 minutes on what proved to be a disappointing first outing for his new club.
Boss Tom Grice managed to get a deal done in time for him to feature on the Isle of Wight and is hopeful Barsa can have a big impact for his side in their final nine games of the Wessex Premier season.
Strangely, Barsa had been due to make his bow for Boro - where he has been training for several months and is currently studying at the University of Portsmouth - in their 4-0 Portsmouth Senior Cup win over US Portsmouth at Privett Park last month.
But unfortunately for the young gun his registration did not go through in time to play a part in Boro's victory and despite not making a first-team appearance for Gosport as of yet, Grice says his parent club boss Shaun Gale is keen to get regular updates on his progress while with at the Victory Stadium.
‘It wasn’t a great game for him (Alex) yesterday in terms of our overall contribution as a team wasn’t good enough,’admitted the US Portsmouth manager.
‘He was trying very, very hard but, as a team, we were just not getting the rub of the green.
‘I’m hoping between now and the end of the season we can get nine more games out of him.
‘I’m in close talks with Gosport in terms of how he’s getting on. They want to know all about him.’
Barsa was unable to make a winning start to life with US Portsmouth as Cowes went ahead through Jake Watson after 17 minutes in their league meeting.
Finley Phillips doubled the Isle of Wight side's advantage on the half-hour but the visitors had hope as Luke Slade pulled a goal back on 57 minutes.
But a day of frustration was completed when Ji Nash capped the scoring with his strike on the hour mark. Grice added: ‘The damage was done when they scored their first goal I felt. It was against the run of play, we had quite a bit of possession, we created chances - the big difference us and Cowes were the chances they had they buried - it’s as simple as that.
‘We felt we got ourselves back into a position where we could have done that at 2-1 but we just didn’t do enough in terms of composure in front of goal.’