The owner of Foxy Bingo, PartyPoker and PartyCasino said like-for-like revenues dropped three per cent to 398m euros (£352.2m) in the six months to June 30.
In its first set of results since the merger of Bwin and PartyGaming in March, the group said it came up against stronger comparatives with the previous year, which was boosted by the World Cup.
Revenues at its poker business declined 10 per cent to 104.9m euros (£92.8m) amid greater competition, including a campaign from rival 888 fronted by former Australian cricketer Shane Warne.
Underlying profits fell 21 per cent to 72.4m euros (£64.1m) after the group, which generates a quarter of its income in Germany, was hit by increased gaming duties as it launched in newly regulated markets.
Bwin said the number of new poker players signing up to its brands increased six per cent to 373,700 in the period, but active player days were down 11 per cent.
Revenues at its bingo arm were down eight per cent to 33m euros (£29.2m) amid intense competition in the UK, while sports betting revenues were down two per cent.
But its casino and poker division saw revenues increase two per cent to 124.3m euros (£110m) as the merger consolidated its position as the world’s largest online casino.
The group said revenues and underlying profits would have increased by one per cent and eight per cent respectively if not for the impact of the World Cup, the increased gaming taxes and the closure of its French casino business.
Trading in recent weeks has been “strong” and its poker business saw an improvement in player numbers and revenues after its rival Full Tilt Poker had its licence suspended at the end of June in Alderney and France.
This removed a major competitor and prompted more people to use PartyPoker and Bwinpoker, helping the group’s share of the online poker market to increase to 12 per cent, it said.
The group recorded bottom-line losses of 49.1m euros (£43.4m) compared to profits of 19.7m euros (£17.4m) the previous year.
But shares rallied 10 per cent after it returned to paying an interim dividend, announcing a payment of 1.56p per share.
The company said: “The results for the first half reflect our transition to becoming a global leader in all four product verticals with strong market positions in all key regulated markets.”
It added: “Whilst the regulatory picture can be expected to continue to shift against a challenging macroeconomic and competitive backdrop, our strong brands and market positions, healthy balance sheet and net cash resources mean that we remain confident about the group’s prospects for the rest of the year and beyond.”