Seeking to win one of only three Masters 1000 events he's never claimed, Federer dealt with the swirling wind inside the 10,500-seat stadium at the Foro Italico, coming to the net often to finish points.
Federer, though, said his ranking isn't that important.
"I look at the big picture and what is important to me is just to be in the top 10 and if I am No. 2 or not at the French Open doesn't change anything, and it doesn't change anything for Rafa," Federer said. "That I was able to win Madrid was amazing, and that is what I look at right now -- not the rankings."
Federer next plays former No. 1 Juan Carlos Ferrero, the 2001 Rome champion.
Federer won 18 of 23 points at the net and held a 24-13 edge in winners against the 38th-ranked Berlocq in their first meeting.
Federer has reached the final twice in Rome, losing to Felix Mantilla in 2003 and to Nadal in a fifth-set tiebreaker in 2006.
While his ranking improved to No. 2, Federer is seeded No. 3 this week.
Federer considered skipping this tournament to stay fresh after playing a full week in Madrid, but said he decided to play "this morning after practice."
With the top eight seeds getting first-round byes, it gave him an extra day off.
"At least here we have two days off, which can be a lifesaver," he said. "I don't think I would have played this tournament if I would have had one day off."