champion echoed the sentiment, saying she liked the new courts at the Caja Magica.
"I think these clay courts are really good," she said. "I think they're a little bit faster than the ones I was practicing on in Paris. For me, that's always a good sign."
Rafael Nadal and Novak Djokovic were even more enthusiastic about the removal of the blue clay, which both players had heavily criticized for being slippery after early exits last year.
"I think that obviously the court last year was not up to the level that we needed," said Nadal. "It was not prepared to be a competitive court.
"But the courts are impressive this year. In Madrid, we have the problem of the dry climate, so it's very difficult to have the clay that settles down properly, a clay that's the same as in other places. I think this year we have managed to have good clay here."
Djokovic called the traditional red clay "great," adding that everything he had heard from other competitors was "positive." The world's top-ranked player had threatened to not come back unless the blue clay was discarded.
Roger Federer won in MAdrid last year despite the challenge the slick courts posed. The Swiss star was nevertheless pleased with the decision to go back to a standard playing surface, saying that the new courts were the best he had seen at the event.
"I don't know if that was due to the color, but this tournament has, in the past, had issues with the quality of the court," Federer said. "I think through what happened last year, you know, the controversy around the blue clay, I think it was a big eye-opener to have a proper court here now."
Nadal, Djokovic, and Federer have first-round byes.
In Williams' opening match, Putintseva broke her serve early to take a 3-1 lead in the first set. But Williams soon settled down after breaking serve and, once through the tiebreaker, dominated the second set.
"I felt a little sluggish out there, but I'm happy I was able to win the match," Williams said. "Honestly, I obviously have to and want to play better as each match goes on."
She next faces Lourdes Dominguez-Lino of Spain.
Serena's sister Venus withdrew early Sunday morning before her first-round match due to back problems.
Also in the first round, formerly top-ranked Caroline Wozniacki was ousted by Yaroslava Shvedova of Kazakhstan 6-3, 6-4.
Shvedova overcame nine double faults by converting five of 15 break chances to see off the 10th-seeded Wozniacki.
Fourth-seeded Agnieszka Radwanska of Poland eased past Tsvetana Pironkova of Bulgaria 6-2, 6-4 and will play Britain's Laura Robson.
Other seeded winners included Angelique Kerber of Germany, France's Marion Bartoli, and Dominika Cibulkova of the Slovak Republic.