By Kylie MacLellan
Kvitova, who had never won on grass until last year's Wimbledon, needed less than an hour to dispatch America's Alexa Glatch 6-2 6-2 and Pironkova soon followed with a 6-2 6-1 win over Italian Camila Giorgi.
At 4-2 down in the second set Glatch, wearing strapping on her left leg and ankle, battled hard to stay in the match, saving two break points before eighth seed Kvitova fired a powerful crosscourt backhand past her to take the game.
As fans outside the court strained to catch a glimpse of the action, the 21-year-old left-hander polished off her win with an effortless ace to set up a second-round clash with Britain's Anne Keothavong.
It was a similar story on court 19 as 23-year-old Pironkova, who last week lost to Serena Williams in the American's first match back after nearly a year off, broke Giorgi in the second game to take an early lead.
A double fault by the error-prone Italian handed Pironkova the first set and she stormed to a 5-0 lead in the second with her powerful serve too much for the 19-year-old to handle.
She will face Croatia's Petra Martic in the second round.
Despite losing the first set, Martinez Sanchez, absent from last year's tournament due to a knee injury, appeared in charge from the start, running her 26-year-old opponent all over the court with well placed shots to take the match 5-7 6-4 6-3.
Over on Court 19, as the sun did its best to break through the clouds over the All England Club, Petkovic was handed an early break by world number 139 Gacon, who netted the ball twice to give the German a 4-2 lead in the first set.
Although the 30-year-old fought on, several times coming close to breaking back, she failed to follow through, slapping her thigh in anger as Petkovic cemented her lead to secure a second round match against Canada's Stephanie Dubois.
(Editing by Ed Osmond)