Nadal made short work of Argentinian Horacio Zeballas in a second-round match postponed from Thursday due to the rain.
His 6-2 6-2 6-3 success set up an intriguing third-round meeting with 28th seed Hewitt today.
“It’s always important to play a little bit better every day,” said Nadal, who had a brief wobble in the third set.
“I’m happy for the victory, but I hope to keep improving.”
Hewitt needed five sets to beat Denis Istomin 1-6 6-3 6-4 2-6 6-2.
Andy Murray survived a monumental mid-match slump to beat Marcos Baghdatis. World number four Murray was in the comfort zone after winning the opening two sets before completely losing the plot, gifting his opponent seven successive games and a route back into the match.
But after going a break down in the fourth set on a sunny Suzanne Lenglen Court, the 23-year-old finally woke up to win 6-2 6-3 0-6 6-2 in two hours and 33 minutes to set up a last-16 clash with Tomas Berdych.
Defending champion Roger Federer produced a near-identical performance to his opening two wins to ease past Julian Reister 6-4 6-0 6-4 and become the first man to reach the fourth round.
“With my own form, I’m very happy,” said Federer, who will play Stanislas Wawrinka after the 20th seed beat Fabio Fognini 6-3 6-4 6-1.
Third seed Novak Djokovic had few problems dispatching Kei Nishikori 6-1 6-4 6-4.
He will face Victor Hanescu (31), who beat Yuri Schukin.
Last year’s runner-up Robin Soderling beat Albert Montanes 6-4 5-7 6-2 6-3, Jo-Wilfried Tsonga (8), got past Thiemo De Bakker 6-7 (6/8) 7-6 (7/4) 6-3 6-4, and Marin Cilic (10), saw off Leonardo Mayer 6-4 3-6 7-5 6-7 (5/7) 6-4.
On a hectic day of catch-up for second-round matches, ninth seed David Ferrer progressed after Xavier Malisse was forced to retire at 6-2 6-2 2-0 down. There were also wins for 2003 champion Juan Carlos Ferrero (16), seventh seed Fernando Verdasco, 22nd seed Jurgen Melzer, Nicolas Almagro (19) and Philipp Kohlschreiber (30).
The only shock saw 12th seed Fernando Gonzalez dumped out 6-3 6-4 6-3 by Oleksandr Dolgopolov Jr.
Ivan Ljubicic (14) survived with a marathon 6-2 6-7 (8/10) 4-6 6-1 10-8 victory over Mardy Fish, while Thomaz Bellucci (24) also needed five sets to beat Pablo Andujar 1-6 6-32-6 6-4 6-2.
In the ladies competition, Svetlana Kuznetsova’s defence of her French Open title ended tonight after she was dumped out of Roland Garros in round three by Maria Kirilenko.
Kirilenko wrapped up a 6-3 2-6 6-4 victory on Court One late last night.
Serena Williams faces 29th seed Anastasia Pavlyuchenkova having trounced Julia Goerges 6-1 6-1.
Four-time champion Justine Henin extended her winning streak to 23 matches and 39 sets by polishing off Klara Zakopalova 6-3 6-3.
The 22nd seed will now face Maria Sharapova after the Russian 12th seed’s 6-3 6-3 success over Kirsten Flipkens. Marion Bartoli (13) beat Olivia Sanchez with a 7-5 6-2 win.