"I thought it was a high, intense match in the first sort of ten games. Then I was able to pull away," Federer said. "I had a good 20-minute stretch where I was really able to stretch the lead, and that was key today."
Krajinovic had his nose out in front early, with a break of serve in the third game of the first set. But he promptly lost serve in the next game. He then had a break point at 5-5, but Federer saved it with an unreturnable serve. Before Krajinovic could blink, he'd lost the next two games.
Krajinovic, the man who prevented an all-Swiss rematch by winning a third-set tiebreaker over Stan Wawrinka, is ranked No. 103, but plays like he should be ranked much, much higher. He's shown signs of a top level before, like when he reached the ATP Masters 1000 final in Paris in 2017. The Serbian has struggled to string together wins, but things may be shifting back up as he qualified and and beat two seeds in Indian Wells, and won two rounds in Miami.
The 27-year-old Krajinovic has also given the 20-time Grand Slam champion trouble before, winning a set in their first-round encounter in Basel. Federer went on to win the title.
"I thought I served very well, because Filip can return very well, especially on second serve. I know I could feel the pressure maybe, to some extent, if I don't make the first serves," Federer said. "But I still kept going after them, and I was able to hit my spots and keep the pressure on and shorten points as the match went on."
This time, no set would be lost as Federer turned the match into a lesson, leaping ahead 3-0 and never looking back. In the final game at 5-3, he almost served four aces: the one on match point was overturned by a challenge. He would hit 14 aces to Krajinovic's two.
"Oh, he thought it was in, and that was the conversation [at the net]," Federer said. "But then I'm thinking, why did he think that? Because it was quite clearly out. But it felt close for me. But thank God it was 40-Love and not much closer and then you end up losing the match because of something like this after having a conversation with your opponent already before it's actually over."
After surviving a testy three-set battle in his first match, against Radu Albot, Federer moves comfortably into an encounter with Daniil Medvedev. Federer will be very ready for the Russian, having beaten him twice last year.
"He's clever how he plays the court, because he can play it up and down, and he's unusual when he plays from back," Federer said. "He plays more flat than actually loopy like what [Dominic] Thiem does or Rafa [Nadal] or Stan [Wawrinka] does. He plays it more flat from the back. It's a bit of a different approach."