Emma Raducanu returned to action for the first time since early October, but could not stop Great Britain from being knocked out of the United Cup.

Raducanu pulled out of her season-opener against Naomi Osaka on Sunday due to an ongoing foot injury, but returned on Monday, losing to Maria Sakkari in three sets.

Great Britain needed to win to advance to the quarter-finals, but Sakkari secured a 6-3 3-6 6-1 win, her first ever over Raducanu, to follow Stefanos Tsitsipas' 6-4 1-6 7-6 (7-4) victory over Billy Harris earlier in the day.

Those two victories were enough to secure Greece a place in the last eight and top Group E, though they could not complete a clean sweep, with Great Britain rallying to win the mixed doubles.

When there's a will, there's a way @mariasakkari defeats Raducanu 6-3 3-6 6-1 to put Team Greece into the quarterfinals. pic.twitter.com/p5NrHZybCl

— United Cup (@UnitedCupTennis) January 5, 2026

Elsewhere, Poland kept their hopes of qualifying for the next round alive in Group F.

Iga Swiatek and Hubert Hurkacz led the charge for Poland in a rematch of the 2024 championship game, with the latter pulling off a stunning victory on his return.

Hurkacz had not played since June but looked flawless back out on the court as he upset world number three Alexander Zverev 6-3 6-4 in 84 minutes.

Swiatek's tie was slightly less straightforward as she had to come from a set down against Eva Lys to secure her 3-6 6-3 6-4 win, clinching the decisive break in the 10th game of the decider to clinch it.

Poland then followed it up with a win in the mixed doubles, as Zverev's tough day continued.

Data Debrief: Swiatek stands up and fights

Swiatek's United Cup record is now 12-2, with her victory over Lys marking her 31st win in her last 32 matches against players ranked outside the top 40.

It was her second serve that proved decisive. Swiatek won 52% of her second-serve points compared to 39% for the German, after the pair were almost level on first serve (54% for Swiatek, 53% for Lys).