Prague, Czechia, 30 April 2018 | tennis.com.au

The all-Aussie affair at the Prague Open between Sam Stosur and Daria Gavrilova ended on a sour note.

Gavrilova was forced to retire from the contest with scores locked at one set apiece when she injured her right foot running for a Stosur drop shot.

The younger of the two compatriots had done a great job to level the match, having earlier been a point away from a 6-3 3-0 deficit.

But in the opening game of the third set, with Stosur poised to break serve, she was beset by acute pain in what appeared to be her heel or Achilles.

After briefly consulting the trainer, Gavrilova retired on the spot, handing Stosur a path through to the second round where she will face either Denisa Allertova or qualifier Patty Schnyder.

.@bambamsam30 is through to the #PragueOpen second round.

A brave Gavrilova is forced to retire with an injury at 6-3, 4-6. pic.twitter.com/9nKXM7e1bY

— WTA (@WTA) April 30, 2018

“It’s not easy ever to play someone from your own country,” Stosur said.

“We just spent the last two weeks together in Australia practising and playing Fed Cup. We practised two days here as well, so we’re obviously pretty good friends. So it’s not easy to play someone like that, especially in the first round here.”

Stosur began the match brilliantly, dictating play and pounding forehand winners en route to a 3-0 lead.

Gavrilova got on the board in the fourth game but was soon down 5-1, frustrated at her inability to handle Stosur’s pace or control her own shots.

Serving for the set, a loose game from Stosur gave Gavrilova hope, and the fourth seed held serve to tighten scores up at 5-3.

On her second opportunity, Stosur made no mistake serving out the opener and quickly took a 2-0 lead in the second set, consolidating her break in the opening game by landing a succession of powerful first serves in the next.

Suddenly the momentum shifted; Gavrilova reeled off three straight games and held points for a 4-2 lead, only for Stosur to escape with a hold after a titanic sixth game.

But Gavrilova had the momentum now. She was being more aggressive yet barely gave away any cheap points, while Stosur’s game had deserted her. The forehand that served her so well in the first set had become tentative and error prone, and if she missed a first serve, she was barely winning a point behind her second delivery.

Gavrilova built a 5-3, 30-0 lead only for another momentum swing to ensue; Stosur rediscovered the sting in her forehand and Gavrilova was misfiring again.

Yet although Stosur broke back, Gavrilova steadied in the following game, scorching a running forehand winner up the line and drawing an error from the veteran on the following point to send the match to a third.

https://twitter.com/WTA/status/990915148717031425

Three points later, it was all over.

Stosur reached the final in Prague in 2016 and said she was pleased to be back in the Czech capital.

“It’s a really good crowd, many people come out to watch, it’s a beautiful city – it’s a perfect place for me to start my claycourt season,” she said.

“It’s great to be out here in the sunshine and to be playing good tennis.”