Federer fields questions from the media during Day 4 of the Miami Open at the Crandon Park Tennis Center. Getty

The good news for Roger Federer at the Indian Wells Masters was that he maintained his No. 1 ranking in a slim lead over Rafael Nadal. The bad news for the Swiss star was that he dropped his first match of the year, falling to Juan Martin del Potro in the final, 6-4 6-7 7-6.

Federer will look to regain the illustrious form that preceded him at the Miami Masters on Saturday afternoon when he faces Australian Thanasi Kokkinakis in the Round of 64. Federer is the tournament's defending champion, having defeated Nadal last year, 6-3 6-4. Federer is seeking his fourth Miami Open title.

"Feeling better today,” Federer told reporters Friday after his five-day layoff. “You know, it always takes a few days to recover from a busy and high-intensity weekend. Regardless of how difficult the match was physically, you still have a letdown emotionally, you know, because you’re drained from that perspective."

The setback to Del Potro was Federer's only loss in an otherwise stellar 2018. The 36-year-old owns an excellent 17-1 record heading into Miami and has won 41 sets and lost just six this year.

The ATP rankings are very close. Federer has 9,660 points compared to Nadal's 9,370. Marin Cilic is a distant third with 4,905 points. Federer will need to reach at least the quarterfinals in Miami to maintain his top ranking. There have already been some notable upsets, as Novak Djokovic, David Goffin and Liam Broady were all eliminated in the second round.

Nadal, meanwhile, will not compete in Miami. The Spaniard is battling a hip injury and has not played since Jan. 23, when he retired from an Australian Open quarterfinals match with Cilic.

Federer has been overcome some nagging injuries and fatigue. He has not announced whether he will compete in the French Open. The Grand Slam begins on May 27.

Federer reached the final at Indian Wells. Getty