LONDON >> This was not the Serena Williams the tennis world is used to seeing on Centre Court. It was still good enough for the defending Wimbledon champion to advance to the second round in straight sets.
Struggling on serve and failing to dominate against a 148th-ranked Swiss qualifier playing in her first Grand Slam tournament on Tuesday, Williams labored to a 6-2, 6-4 victory over Amra Sadikovic — the 80th match win of her Wimbledon career.
What looked on paper like a complete mismatch turned into a tighter contest than expected.
"I never underestimate anyone," said Williams, who had only four aces and served five double-faults. "It was a really good match but I don't think it was tougher than I thought. It was definitely tough, but I always expect the best from everyone."
With her mother, Oracene Price, watching from the Royal Box, the six-time Wimbledon champion jumped out to 3-0, running off 13 points in a row, defying her reputation as a slow starter.
"I started fast, that's about it," Williams said when asked what positives she took from her performance.
The 27-year-old Sadikovic, who decided to retire in 2014 to work at a tennis club in Basel but eventually was talked into returning to the tour, made things tricky for Williams. She took a 2-1 lead in the second set and stayed even until the final game, when she was broken while serving at 4-5.
The match ended on a successful line challenge by Williams after she hit a backhand return that was called long. When the video replay showed the ball hit the back of the line, Williams grinned and threw up her arms in triumph.
Since winning last year's title, Williams has come up short in the majors, losing in the semifinals at the U.S. Open and finals of the Australian and French Opens. She needs one more Grand Slam championship to equal Steffi Graf's Open-era record of 22 titles.
On the men's side, second-seeded Andy Murray followed Williams on Centre Court and cruised to a trouble-free 6-2, 6-3, 6-4 win over Liam Broady, a British wild-card entry ranked No. 235.
In the first all-British men's meeting at Wimbledon since 2001 and first at a Grand Slam since 2006, Murray was in command from start to finish. The 2013 Wimbledon champion toyed with the left-hander, who failed to break Murray.
"It's not that easy playing someone you know so well, but I did OK," Murray said.
Murray piled up 31 winners, including a forehand drop shot on match point.
Murray finished the match just before the first rain delay of the tournament. Tarps were pulled over all of the outside courts, and the retractable roof on Centre Court was closed for the ensuing women's match between Svetlana Kuznetsova and Caroline Wozniacki.
Also reaching the second round with straight-set wins were seeded Frenchmen Richard Gasquet and Jo-Wilfried Tsonga.
No. 7 Gasquet swept past Britain's Aljaz Bedene 6-3, 6-4, 6-3, while No. 12 Tsonga got past Spain's Inigo Cervantes 6-4, 7-6 (5), 6-4. Gasquet reached the Wimbledon semifinals last year, while Tsonga made it to the semis in 2011 and 2012.
Fourth-seeded Stan Wawrinka, who had lost in the first round at the All England Club five times, beat 18-year-old American Taylor Fritz — the youngest player in the men's draw — 7-6 (4), 6-1, 6-7 (2), 6-4.
That set up a second-round match against Juan Martin del Potro, the 2009 U.S. Open champion who beat Stephane Robert of France 6-1, 7-5, 6-0 in the big-hitting Argentine's first appearance at Wimbledon since 2013 after a series on surgeries on his left wrist.
No. 15 Nick Kyrgios kept his cool — and hit another between-the-legs winner — as he beat 37-year-old Radek Stepanek 6-4, 6-3, 6-7 (9), 6-1.
The Australian was broken while serving for the match at 5-4 in the third set, and squandered two match points in the tiebreaker. He was also warned for an audible obscenity, but otherwise kept on his best behavior and settled down to dominate the fourth set.
"A couple years ago, if I get broken there, I'm probably going to end up losing the match," Kyrgios said. "It's just maturity."
The highlight of the match came when Kyrgios hit a between-the-legs "tweener" from behind the baseline that sailed over Stepanek's head at the net and dropped in for a perfect lob winner in the opening game of the third set. It was reminiscent of the tweener he hit for a winning drop shot in his upset victory over Rafael Nadal two years ago.
Kyrgios set up an intriguing second-round match with Dustin Brown, another flashy shot-maker who beat Nadal here last year.