Mendy, a 19-year-old Senegalese forward, opened the scoring for the visitors at the New Balance Arena, continuing a curious record of having scored all three of his career Serie A goals against Atalanta.
According to Calciomercato.com, an Inter scout was present specifically to track the progress of the young forward and his midfield team-mate, Swiss-born Romano.
"An Inter Milan scout was present at the New Balance Arena for the match between Atalanta and Cagliari, with the aim of closely following the Swiss midfielder born in 2006 and the Senegalese forward, who scored the goal that gave Pisacane's side their temporary lead," the outlet reported.
Romano, a product of Atalanta's own academy, joined Cagliari this summer on loan with an obligation to buy for a total fee of around €5.4 million, and only this week announced a switch of international allegiance to Italy, having previously been eligible to represent Switzerland at senior level.
Both players are increasingly becoming influential figures for Fabio Pisacane's side, who currently sit fourth in Serie A after a strong start to the season, and their growing importance in Sardinia has placed them on the radar of the Scudetto champions in the short term.
Cagliari coach Pisacane described Romano as "a gem" after the win, while Mendy's decisive contribution in front of goal further underlined his development as one of the more promising young forwards in the division this season.
Cagliari have collected nine points from four matches so far, with their only defeat coming against Inter earlier in the campaign, underlining the growing reputation of Pisacane's young squad in Serie A this term.
Inter have made a habit of scouting Italy's smaller clubs for emerging talent in recent seasons, and the presence of a scout at the New Balance Arena underlines the club's continued focus on domestic recruitment alongside their South American scouting network in Argentina and Brazil.