Online gaming firm PartyGaming grew underlying interim profit by 14% and has continued to trade in line with expectations at the start of the second half. The group, which is merging with Austrian rival bwin, reported underlying earnings before interest, tax, depreciation and amortisation (EBITDA) of €48.1m in the six months to 30 June, up from €42.3m last time.Revenue jumped 30% to €181.2m, driven partly by acquisitions, and came despite a bigger than expected hit on the poker business from the World Cup in South Africa, as flagged last month.That cut revenue at the unit to €64.4m from €71.2m, though that was more than offset by gains in casino, the star performer with a 23% increase to €76.4m, bingo and sports betting."Whilst the macroeconomic and competitive environments remain challenging, we remain confident about the Group's prospects for the rest of the year and beyond," said chief executive Jim Ryan.