Federer, 36, had taken a set from Federico Delbonis 6-3 with the second tied at 2-2 when rain stopped play, which is expected to resume late on Sunday
Rain halts Roger Federer's Indian Wells opener and Grigor Dimitrov crashes out
Defending champion Roger Federer's opening match was put on hold on Saturday when play at the Indian Wells ATP Masters was suspended after heavy rain swept through the California desert.
Federer, 36, had taken a set from Federico Delbonis 6-3 with the second tied at 2-2 when rain stopped play. The start of the match had been delayed several minutes by light rain in a precursor of worse weather to come.
With the showers expected to continue, organisers eventually suspended play for the night, with the match to resume on Sunday.
One women's match had yet to be completed and another did not even make it on court, and those two were also to be completed on Sunday.
Federer and Delbonis will be the third match on stadium court on Sunday after 10th seeded Novak Djokovic plays his opener against Japan's Taro Daniel. Federer is seeking to extend his perfect record this season to 13-0 as he hopes to make history and capture his sixth title.
The age-defying Swiss player has already won two titles in 2018, claiming his 20th grand slam crown at the Australian Open in January.
In men's play earlier, world No 4 Grigor Dimitrov slumped to a shock 7-6, 4-6, 6-3 defeat to Spain's Fernando Verdasco. Dimitrov continues to struggle in Indian Wells. The 26-year-old Bulgarian No 1 has never made it past the third round in seven appearances.
Dimitrov reached the final earlier this year in Rotterdam, where he lost to Federer. That came after a breakthrough 2017 which saw him win four titles, including Sofia, Cincinnati, Brisbane and the ATP Finals.
Verdasco, 34, is making his 15th straight appearance in Indian Wells and trying to improve on his 2009 quarter-final run.
"It is an amazing feeling when you come to a tournament like this and in a stadium with a good atmosphere against one of the top players in the world. You know you're able to do your job and have a good day and win the match," Verdasco said.
"So it was a really good feeling. I am super happy to win and come through this tough opponent and this tough round.
"I am just going to enjoy the victory and try to keep it going in the next round and make it as far as possible."
Fifth seeded Dominic Thiem defeated teenager Stefanos Tsitsipas 6-2, 3-6, 6-3 in a second round match.
Thiem moved through to a third round meeting with 30th seed Pablo Cuevas, of Uruguay, who beat Canadian Denis Shapovalov 7-6, 6-3.
Thiem, 24, is hoping to improve on last year's quarter-final finish at Indian Wells, one of the biggest events on the tennis calendar outside of the four majors.
Other men's winners on Saturday included American Taylor Fritz, Czech Tomas Berdych and South Korea's Chung Hyeon.