Keothavong out, Schiavone through
Italian Schiavone conceded just three games in the match as she swept past her opponent 6-1 6-2 with considerable guile and precision from the back of the court.
Schiavone took the opening set with consummate ease, holding serve without any problems and ensuring that Cadantu was only able to record one game.
The second set was equally one-sided as Schiavone powered winners while her opponent toiled behind the baseline with little rhythm on serve.
It was a comfortable victory for the Italian, who took the second set for the loss of just two games.
Schiavone will next take on Mirjana Lucic of Croatia, who defeated Keothavong 2-6 7-5 6-4 in their first-round match.
Third seed Maria Kirilenko was forced to withdraw from the tournament at 3-6 7-5 0-0 with Sloane Stephens of the USA progressing at her expense.
Kirilenko took the opening set in confident fashion, but was unable to continue after an injury sustained during the second set forced her to end the match before the start of the third set.
Stephens will play Hungary's Timea Babos, who was also handed a walkover after Anastasija Sevastova of Latvia withdrew injured.
The Spaniard took a hard-fought opening set with a solitary break of serve with the two players locked at 5-5 and heading for a tie-break.
The doughty Tatishvili responded in impressive fashion to take the second set 6-4, but she could not sustain her intensity and folded in the third.
Garrigues held her composure and found considerably more energy in the final set as she took it for the loss of just a single game.
Garrigues is up against Taiwan's Su-Wei Hsieh, who beat Romanian Irina Begu 6-7 6-3 6-1.
It was not a good day for fifth and sixth seeds Mona Barthel and Marina Erakovic, however.
Barthel was beaten 6-3 7-6(7) by Alexandra Panova of Russia as the German looked devoid of inspiration and was unable to muster a response after losing the first set convincingly.
Panova will play Lucie Hradecka in the second round after the Czech beat Mandy Minella 7-6 6-2.
Erakovic, meanwhile, was dumped out of the competition by Ayumi Morita of Japan as the New Zealander recorded just four games in the two sets.
Morita faces France's Virginie Razzano for a place in the quarters after she battled to a 1-6 6-2 7-5 win over Maria Jose Martinez.
Peer gets Alize Cornet of France after she beat Olga Govortsova of Belarus 6-4 2-6 6-4.