(CNN) -- The 2009 U.S. Open champion Juan Martin del Potro eased into the second round of the Miami Open with a straight sets victory over Brazil's Ricardo Mello.
The Argentine -- who made the semifinals in 2009 but missed the 2010 Florida hard-court event due a long-term wrist injury -- was in devastating form as he raced to a 6-4 6-4 win.
"I really like playing here in Miami. Many South American people come to see the tournament, so we feel really well [supported], and hopefully I'll be better in the next match," the former world No. 4 told the official ATP website.
The 22-year-old, who moved back up to 51 in the world with a semifinal appearance at Indian Wells last week, will face world No. 28 Philip Kohlschreiber of Germany for a place in the third round.
Meanwhile, 2008 Miami champion Nikolay Davydenko of Russia crashed out to South African Kevin Anderson 6-3 6-4 on Wednesday.
Croatia's former world No.3 Ivan Ljubicic was another first-round casualty losing to 154th-ranked qualifier Paolo Lorenzi 7-6 (7) 6-1.
Florida-born James Blake beat compatriot Michael Russell 3-6 7-6 (7) 7-6 (3) in a thrilling evening game, however, fellow American Donald Young's hopes of having another good result at a Masters series event -- following his win over Andy Murray in California -- came to an end as he lost Uzbekistan's Denis Istmoin 6-4 6-3.
Elsewhere, in the women's draw former world No. 1 Dinara Safina won the battle of the comeback kids with a straight sets victory over Australia's Jelena Dokic in their first round match.
Safina and former world No. 4 Dokic both showed flashes of the form that took them to the top of the game, but it was the Russian who ultimately came out on top breaking serve at the end of both sets to triumph 6-4 6-4.
Next up for 91st-ranked Safina is compatriot and world No. 3 Vera Zvonareva, who received a bye through to the second round.
"It will be tough but I have nothing to lose," Safina said of playing the two-time grand slam finalist. "I'll just go out there and enjoy it. Hopefully it will be a strong performance and I can pull off a win," she told the official WTA website.
Defending Miami champion and world No. 2 Kim Clijsters announced she had pulled out of the Pan Pacific Open in Tokyo, scheduled for September, due to safety fears.
The 27-year-old said the move was a reaction to the recent crisis at the damaged Fukushima Daiichi nuclear plant where radiation leaks have been recorded following the earthquakes and tsunami that hit the region.
Clijsters -- who plays Anastasiya Yakimova of Belarus in her opening game in Miami on Friday -- told gathered reporters: "The health and safety of anyone traveling to a potentially impacted area is my top priority and I know the WTA will continue to monitor the situation.
"Most importantly, my thoughts and sympathies are with the people in Japan. It's heart-wrenching to see what they're going through right now," she added.

COMMENT: That juan martin del potro and dinara safina progress to the second round in the tourment in miami