Maria Sakkari was made to work as she battled her way back from a set down to reach the last 16 of the Parma Ladies Open.
The No1 seed lost the first set to Ukrainian qualifier Kateryna Baindl as a shock appeared to be on the cards.
But the two-time Grand Slam semi-finalist showed great spirit to eventually win 6-7 6-2 6-3 after two hours and 45 minutes on court.
Fourth seed Sloane Stephens also had to respond to first-set disappointment before coming through 3-6 6-3 6-4 against Magdalena Frech.
The only other seed in action on Monday was Ana Bogdan (sixth), and she had no such issues as she lost just three games in a straightforward win over Brazilian Laura Pigossi that took just 73 minutes.
At the Tallinn Open in Estonia, Belinda Bencic was the highest-ranked player on court on Monday and the second seed breezed through her first-round clash with local favourite Elena Malygina 6-0 6-2.
Karolina Muchova crushed Jessika Ponchet by the same scoreline, while Barbora Krejcikova, seeded seventh, saw off Ajla Tomljanovic 6-1 7-6 in straight sets.
However, there was no joy for Madison Keys, with the fourth seed going down 6-3 6-2 against Switzerland’s Viktorija Golubic.
Marta Kostyuk defeated Bernarda Pera 6-6 4-6 6-3 and Great Britain’s Katie Boulter dropped only four games in her 6-3 6-1 demolition of Jaqueline Cristian, setting up a second-round date with Bencic.