Growth in Europe's services and manufacturing industries unexpectedly accelerated in July, as an increase in global trade spurred exports.
A composite index based on a survey of euro area purchasing managers rose to 56.7 from 56 in June, London-based Markit Economics said.
Klaus Baader, chief euro-region economist at Societe Generale in London, said growth was "surprisingly robust".
"It looks as if the second half won't show as much cooling as expected," he said.
European stocks gained for a third day following the report from Markit Economics.
The Stoxx Europe 600 Index advanced 1.9% to 253.92. The euro rose 1.3% against the dollar to $1.2919.
An index of euro area services, which account for about 60% of the region's GDP, rose to 56 in July from 55.5 in the prior month, Markit reported.
The data may also show a divergence between economic performance in Germany and in the so-called peripheral euro region, said Ralph Solveen, head of economic research at Commerzbank AG in Frankfurt. Germany's services index surged to 57.3 from 54.8 in June.
The euro area increases "are exclusively attributable to a steep rise in Germany," Mr Solveen said. "They highlight the current split in economic activity within the euro zone."
That will be accentuated as high-deficit countries implement deeper cuts, said Klaus Baader.