The event moved indoors for the first time since the 1912 Stockholm Games, and Sharapova made her Olympic debut amid a din, beating Shahar Peer of Israel 6-2, 6-0.
"You hear a little bit of it, but it's not a big distraction," Sharapova said. "When you see the schedule and you see your name on Centre Court, you know that your match is going to get done. Knowing what the weather forecast was going to be like today, I was pretty happy."
Other winners under Centre Court's retractable cover were Julia Goerges of Germany, who upset recent Wimbledon runner-up Agnieszka Radwanska of Poland, and British hopeful Andy Murray. Play elsewhere was curtailed because of rain, with 27 matches postponed.
There were no such issues at the 1912 Games, played in a pavilion on wood courts painted black. This time the surface is grass, where Sharapova won her first Grand Slam title in 2004 at age 17.
She completed a career slam last month by winning the French Open, and now hopes to add an Olympic medal. She carried the Russian flag in London's opening ceremony Friday after missing the 2008 Games because of a shoulder injury.
Against Peer, the No. 3-seeded Sharapova served well, returned aggressively and swept the final eight games. She improved to 7-0 against Peer.
The No. 24-ranked Goerges also made a successful Olympic debut, hitting 20 aces to beat No. 2-seeded Radwanska 7-5, 6-7 (5), 6-4.
"I didn't really think about it as it's my first time on the Centre Court, and you just go there and enjoy it," Goerges said. "You just play there as you warmed up outside. The courts were different. But that's, for both, the same."
No. 3-seeded Murray returned to the court where he lost this month's Wimbledon final and beat Stanislas Wawrinka of Switzerland 6-3, 6-3.
"I want to be involved in this event for as long as possible," Murray said. "I'm going to give it my best shot."
Murray also defeated Wawrinka in the first full match under the roof, played at Wimbledon in 2009. Murray lost the Wimbledon final three weeks ago to Roger Federer.
Goerges and Radwanska endured some sloppy moments in the early going before they adjusted to the slow indoor conditions. At one point, rain on the roof fell so heavily it was difficult to hear the ball being struck.
Goerges' serve kept her in the match, and she also moved forward effectively, winning 19 of 24 points at the net.
"I felt pretty great there," Goerges said. "My game is to be aggressive, and I know that doesn't suit her pretty well because she's one who wants to create a little bit of angles to play clever on the court."
In the final set she hit a deft drop shot to hold for a 5-4 lead, then broke serve in the last game, whacking a return winner on the first match point.
That ended medal hopes in singles for Radwanska, who is playing doubles with her sister. Less than four weeks ago, Radwanska became the first Polish player to reach a Grand Slam final since 1939, then lost to Serena Williams.
Postponed were first-round doubles matches involving the 2008 gold medal teams, the Williams sisters and Federer-Wawrinka, a men's doubles match with Vancouver's Vasek Pospisil and Toronto's Daniel Nestor and singles matches involving No. 1-seeded Victoria Azarenka, Andy Roddick, Milos Raonic of Thornhill, Ont., and Aleksandra Wozniak of Laval, Que.