The Swiss, who is bidding for a fourth name in Miami, beat Serbia’s Krajinovic 7-five 6-3.
Federer converted simply of 8 spoil points inside the opening set however have become more correct as the healthy stepped forward, completing with 35 winners to 23 unforced errors.
he will face either American Reilly Opelka or Russian Daniil Medvedev subsequent.
Federer hit 14 aces towards Krajinovic and won seventy four% of first-serve factors.
The 20-time Grand Slam champion has gained 14 and misplaced suits at the ATP tour this season.
earlier, Australian world quantity seventy seven Jordan Thompson beat Bulgarian twenty ninth seed Grigor Dimitrov 7-five 7-five to reach the fourth round.
South Africa’s Kevin Anderson endured his return from an arm damage with a 6-4 7-6 (8-6) win over Joao Sousa of Portugal.