The tennis ace's five-month-old daughter, Alexis Olympia, was in the sellout crowd at the Fed Cup in Asheville, North Carolina on Sunday.
Serena, 36, lost her first official match as she and sister Venus were beaten in a doubles dead rubber by the Netherlands.
The mum-of-one, who gave birth last September and had not played a competitive match since her triumph at the 2017 Australian Open, showed glimpses of her prowess and rust during the 6-2 6-3 loss to doubles specialist Demi Schuurs and world number 165 Lesley Kerkhove.
"It's great. It's her first match so I'm glad she got to see it," Serena said on-court at the US Cellular Arena.
Early in the match Serena showed the effects of her lengthy layoff, perhaps most noticeably when she shanked a routine volley that left her bent over in embarrassment.
But shortly after, the owner on an Open-era record 23 grand slam singles titles drew wild cheers when she confidently stepped to the net and stretched out to drive home a superb backhand volley.
Despite the loss, it was a positive step for Serena, who was bedridden for six weeks from a series of complications, including a pulmonary embolism that led to multiple surgeries, after her daughter was delivered by emergency caesarean section.