Total net revenues rose 6% in the four months to 25 October, driven by a 4% jump in digital revenues following a stronger performance from its mobile Sportsbook and more favourable football results.
But while gaming machine revenues rose 6% over the period, retail revenues were flat and over-the-counter revenues dropped 6%.
The firm said it had earmarked £30m worth of savings for next year, which it plans to drive back into its online business.
It added that it now expects full-year operating profit to come in at the higher end of its £260m to £280m range.
Philip Bowcock, interim chief executive, said: "Online has returned to wagering growth in the UK following significant enhancements to our mobile Sportsbook in second quarter and we are making good progress on the gaming and user experience improvements in second half, further helped by the Grand Parade team we acquired in August.
"Looking forward, we remain on track to deliver 2016 operating profit at the top end of our guided range.
"With our significantly improved products and user experience, we are confident that this is the right time to invest further in our online business.
"Therefore, the marketing efficiencies we are announcing today will be reinvested in driving faster digital growth to benefit future performance."
The update came as the company announced a string of non-executive directors, including John O'Reilly, ex-managing director of Coral Interactive; Robin Terrell, former chief customer office at Tesco; and Mark Brooker, former chief operating officer at Betfair.
Shares in the bookmaker were up more than 1% in morning trading.
William Hill has endured a tumultuous 2016, with technical problems hitting its online business and its chief executive James Henderson stepping down amid profit warnings and slumping sales.
Last month the firm called time on a potential £4.6bn merger with Canadian poker firm Amaya after "canvassing the views" of its major shareholders.
The aborted deal came after Mecca Bingo operator Rank Group pulled out of a joint bid with 888 for William Hill.
The gambling sector has seen growing consolidation over the past year, with Paddy Power and Betfair joining hands and Coral and Ladbrokes inking a £2bn merger.
Nicholas Hyett, Equity Analyst at Hargreaves Lansdown, said it was encouraging that William Hill was focusing on its core business rather than "rolling the dice on big strategic moves".
"Having considered mergers with what feels like every other gaming company around, William Hill finally seem to be knuckling down to the job of turning the core business around.
"The online business is back in growth, efficiency savings have been identified and the self-service terminal roll-out is complete.
"The group has also announced a revamped board this morning. Former Coral and Betfair execs bringing industry knowhow, and Tesco's Mark Brooker an increased focus on customers."
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