Krejcikova beat Italy’s Jasmine Paolini in three sets in last year’s Wimbledon final to win her second Grand Slam crown.
But the 29-year-old’s hopes of repeating that memorable triumph were rocked by her 6-4, 6-3 loss to Slovakia’s Sramkova in the opening round of the Wimbledon warm-up event in London.
The defeat extended a disappointing run for Krejcikova since her victory at the All England Club.
She lost in the second round of the recent French Open and missed January’s Australian Open with a back injury that kept her sidelined until May.
Krejcikova, the world number 17, was also beaten in the US Open second round in the last Grand Slam of 2024.
World number 41 Sramkova will face former US Open champion Emma Raducanu in the second round at Queen’s.
Raducanu, who famously won in New York as an 18-year-old qualifier in 2021, made a vibrant start to her grass-court singles season, routing Spain’s Cristina Bucsa 6-1, 6-2 on Tuesday.
The British star revealed before Queen’s that she is still troubled by back spasms that have plagued her for much of a frustrating 2025 campaign.
But Raducanu looked in fine fettle as she brushed aside Bucsa to the delight of the British fans in the Andy Murray Arena.
“I must say I was quite locked in today,” the world number 37 said. “I’m very pleased with my performance. I was a little bit nervous at the beginning. It’s my first time playing on this court at Queen’s and the support is incredible.”
“I just want to stay here playing as many matches as I possibly can,” she added.
In the first women’s action at Queen’s since 1973 – the tournament has been solely an ATP men’s event for 52 years – Raducanu was joined in the second round by two of her compatriots.
Katie Boulter won 7-6 (7/4), 1-6, 6-4 against Australian qualifier Ajla Tomljanovic.
Heather Watson beat world number 27 Yulia Putintseva 6-4, 6-3 to book a clash with former Wimbledon champion Elena Rybakina. (AFP)