Easy victory for Serena Williams in Miami opener against Monica Niculescu

World number one Serena Williams launched her bid for an eighth title at the Miami WTA and ATP Masters on Saturday with a victory over Monica Niculescu.

The 33-year-old American defeated the cagey Romanian for the second tournament in succession, showing no sign of the knee injury that forced her to forfeit her Indian Wells quarter-final in a 6-3, 6-1 win.

"It was a little sore in practice, but it was OK today," Williams said of her knee. "I really didn`t feel it today, to be honest. 

"Once you step out on the court you have so much adrenaline going. The adrenaline kind of kills it. So I was surprised. I felt pretty good."

Williams, who had more trouble beating spin-merchant Niculescu in her opening match at Indian Wells, needed just an hour and 21 minutes to get past her in this match postponed from Friday when rain washed out the night session at Crandon Park.

"I don`t think I had that many unforced errors, especially in comparison to the last time I played her," Williams said. "I think that was a little bit better."

The 33-year-old American star next faces 15-year-old compatriot Catherine "CiCi" Bellis.

Bellis advanced with a 6-2, 6-1 win over 29th-seeded Zarina Diyas on Friday.

In men`s action, 11th-seeded Jo-Wilfried Tsonga celebrated his return from a lingering arm injury with a 6-4, 3-6, 6-3 win over American Tim Smyczek.

Tsonga, who hadn`t played since France`s Davis Cup tie against Switzerland in November, said he was satisfied with his 2015 debut.

"I didn`t expect to play my best tennis today ever, but I`m happy the way I managed my match," said the Frenchman. "I played pretty solid, I just had a little hole in the second set.

"But it`s normal when you didn`t play since couple of months now," he added. "I hope it`s going to be better and better, but for first match was already something good for me."

Tsonga finished with 30 winners and 36 unforced errors against his 74th-ranked opponent. The former Australian Open finalist converted two of his break point chances and delivered 10 aces.

Tsonga next faces good friend and Davis Cup team-mate Gael Monfils, a 3-6, 6-2, 7-6 (7/4) winner over Serb Filip Krajinovic.

"It`s always special to play a good friend," Tsonga said. "But anyway, we know both that on the court there is no friends. But of course, whatever happens on court, we are good friends outside."

Elsewhere on a schedule catch-up day, Japan`s fourth seed Kei Nishikori defeated Russian Mikhail Youzhny 6-2, 6-1 then had to wrestle after his media conference with a wiggly bulldog which has somehow been adopted as a tournament mascot and splashed all over social media.

"Just met Manny The Frenchie! He is very famous! :) I think more fans than me," tweeted Asia`s top player and the 2014 US Open runner-up.

In other matches, Spanish sixth seed David Ferrer beat Argentine Federico Delbonis 6-1, 6-1, France`s Gilles Simon, the 12th seed, stopped Mikhail Kukushkin 6-3, 6-7 (5/7), 6-0.

Ernests Gulbis, seeded 14th, was defeated for the seventh time in eight matches this year, falling 6-2, 6-4 to American Jack SockIn the women`s draw, there was a second-round shocker for Canadian sixth seed Eugenie Bouchard the 2014 Wimbledon finalist who was beaten 6-0, 7-6 (7/4) by 113th-ranked German qualifier Tatjana Maria.

Seeds Sara Errani, the Italian 11th seed and 13th-seeded German Angelique Kerber both advanced in their delayed second-round matches.

Errani beat Anastasia Pavlyuchenkova 6-1, 7-6 (7/5) and Kerber dismissed Briton Heather Watson 7-5, 3-6, 6-4.

Order reigned in the third round for favorites.

Former number one and fourth seed Caroline Wozniacki beat Estonian Kaia Kanepi 4-6, 6-1, 6-3, eighth seed Ekaterina Makarova beat Elina Svitolina 6-0, 6-4 and Andrea Petkovic, seeded ninth, beat France`s Kristina Mladenovic 6-0, 6-2.

Russian Daria Gavrilova followed up her upset of second-seeded Maria Sharapova by beating Japan`s Kurumi Nara 6-0, 7-6 (7/5).