Pre-tax profits for the 26 weeks to June 29, excluding exceptional items, grew 10.1% to £24.5 million while total sales rose 14.9% to £375 million.
The chain's core UK market grew like-for-like sales by 11.3% including a 1% benefit from the impact of armchair football fans dialling up - or increasingly going online - to order.
Sales were bolstered by digital investment, promotions and products including a "Carnivale" range to coincide with the tournament and a "Footy Fan Feast" offer.
New chief executive David Wild said it was a strong first-half performance and pledged to drive forward the web and smartphone offering, with mobile expected to become the most popular channel in 2015.
But the group endured a tough six months in Germany where like-for-like sales fell by 1.7% as it shut poorly-performing stores and cut marketing spending as the business undergoes a "transition period".
Republic of Ireland sales continued a "solid recovery" to grow 3.2% while in Switzerland, after a slow start to the year, they were up 2.9%.
Mr Wild, the former Halfords boss whose interim role as chief executive was made permanent at the end of April, said Domino's had now seen three successive quarters of double-digit like-for-like sales growth in the UK.
He added: "I am especially pleased at the continued success of our e- and m-commerce platforms showing how customers enjoy and appreciate the benefit of ordering online. We are investing further to drive this even harder."
UK online sales grew 30.6% to £204.7 million and now account for 69.7% of delivered sales, up from 63.3% the year before. The group said 38.3% of online orders were taken through a mobile device, up from 27.5%.
Mr Wild said: "We anticipate that mobile will become our most popular ordering channel in 2015."
He confirmed that Domino's still plans to open 40-50 UK stores this year as it seeks to maximise the potential of the "significant opportunity" that remains in the market.
"Equally, the UK performance illustrates the opportunity for the Domino's brand in other markets, as further evinced by its success elsewhere in the world.
"Conditions in Germany have proved to be challenging, but I remain determined that we follow our agreed strategy and develop a viable business model."
The group opened 11 new stores in the period and closed one, creating 300 new jobs, expected to rise to more than 1,300 by the end of the year.
Numis analyst Sahill Shan said today's figures were mixed, adding: "A highly positive UK showing is tainted by a further disappointing international showing."
The Domino's business in Europe, which is separate from its counterpart in the US, has 868 outlets, including 670 in England, 56 in Scotland, 33 in Wales, 21 in Northern Ireland and 48 in the Republic of Ireland.