* FTSEurofirst 300 flat, FTSE 100 up 0.2 pct
* UK supermarkets rise as GDP reading is revised up
* FTSEurofirst poised for 1st weekly loss since June
By Francesco Canepa
LONDON, Aug 23 (Reuters) - European bourses were little changed early on Friday, with British stocks outpacing the broader market after data showed the country's economy was growing more quickly than first thought.
Shares in British supermarkets Morrison and Sainsbury rose 1.8 percent and 1.2 percent, respectively, having extended gains after Britain's second-quarter GDP figures were revised up to show a 0.7 percent increase.
They helped London's FTSE 100 rise 0.2 percent to 6,460.17 points, outperforming the pan-European STOXX 600 , flat at 303.55 points, and the euro zone Euro STOXX 50 index, down 0.3 percent at 2,804.41 points.
The estimate revision came after a raft of forecast-beating data from Britain and other European economies, such as Germany, in recent weeks, in contrast with signs of slowing growth in emerging economies.
"Macro momentum in the UK is one of strongest in any of the major developed countries right now," said Nick Nelson, global equity strategist at UBS, who expected the FTSE to end the year at 7,000 and the STOXX 600 at 325 points.
"We're bullish on the UK...specific domestic themes. Even within Europe, the areas (of the market) that are improving are the domestic stories, not the emerging market."
The Euro STOXX 50 has risen 13 percent since early July as improving European economic data persuaded investors to switch back from emerging markets.
But the index was on track for its first weekly loss since early July after expectations of reduced bond buying from the Federal Reserve caused some profit taking on two-year highs in the early part of the week.
"We did see a little bit of a correction lower but, in a wider perspective, conditions, are somewhat stretched still," said Dag Muller, a technical analyst at SEB in Stockholm.
Muller said a deviation of 6 percent above or below the index's 26-week exponential moving average tended to cause "overbought" and "oversold" conditions. The Euro STOXX 50 was roughly 3.5 percent above its 26-week average on Friday.
The broader FTSEurofirst 300 was flat at 1,218.95 points, putting it on course for its first weekly loss since late June. Volume was thin at 24.1 percent of the index's full-day average for the past three months.
Shares in Commerzbank were a standout performer on Friday, rising 2.3 percent after a report suggested the German government could sell its 17 percent stake in the struggling bank to another European lender.
Traders said signs that negotiations were underway were positive but cautioned any deal was unlikely to come before the German election in September and that the government may need to take further steps to attract buyers for its stake.
"I think after the election something will happen, but you have to make the asset more attractive with a guarantee of bad loans," a trader in Frankfurt said.