* U.S. 3rd-quarter GDP growth beats expectations
* Greece uncertainty keeps euro under pressure
* Spain seen on track to correct problems in financial sector
* Euro zone ministers to hold call on Greece next week
NEW YORK, Oct 26 (Reuters) - The euro traded flat against the dollar on Friday following three straight days of losses, but persistent concerns over whether Spain will ask for a bailout to address its problems and worries about Greece were expected to weigh on the currency.
A request by Spain, the euro zone's fourth largest economy, for help would be considered a positive for the euro because it would allow the European Central Bank to start buying its bonds, which would lower borrowing costs of the highly indebted country.
``People are still concerned about Spain asking for a bailout and Greece remains a problem too. I remain bearish on the euro,'' said Lutz Karpowitz, FX strategist at Commerzbank.
Though the euro was down 0.7 percent on the week, it was still up 0.7 percent so far in October. But in addition to worries about Spain, investors remained uneasy about Greece's ability to secure another loan from its creditors.
The European Central Bank and the European Commission said in a joint statement that Spain was on track to correct the problems in its financial sector, but needs more decisive action to deal with challenges facing some banks.
The euro briefly gained after the International Monetary Fund said important progress was being made in reforming Spain's financial sector.
The euro hit a low of $1.2881, its lowest level since Oct. 11. It last traded at $1.2934, flat on the day.
The euro dropped sharply against the safe-haven yen to last trade at 103.02 yen, down 0.8 percent on the day.
Concerns about Greece were at the forefront after the International Monetary Fund that said Greek debt would be above the target agreed with international lenders. The Greek government said a deal on Athens' latest austerity package was being held up by opposition from a coalition ally.
Finance ministers of the 17-member euro zone, called the Eurogroup, will hold a conference call next Wednesday to discuss Greece, the spokesman for the Eurogroup president said on Friday.
Grim economic data from the euro zone has also weighed on the euro this week.
Traders said the single currency was likely to be caught in a $1.2800/1.3200 range until Spain asks for aid. Offers were cited around $1.2960 and above $1.3000.
Stronger-than-expected growth in the United States did little to buoy the dollar.
The Commerce Department said U.S. GDP expanded at a 2.0 percent annual rate in the third quarter. That follows 1.3 percent growth in the second quarter and was just a tick above the 1.9 percent estimate of analysts polled by Reuters.
``What we have seen transpire over the past week is an intense focus on earnings and the paring back of forecasts for global growth, so today's GDP data should soothe some of those fears,'' said Camilla Sutton, chief currency strategist at Scotiabank in Toronto.
``The focus should now rapidly shift to next week's nonfarm payrolls and U.S. elections the following week,'' she said.
The U.S. government will release its closely watched monthly jobs report on Friday.
YEN SEEN VULNERABLE
The dollar fell against the yen after touching a four-month high on expectations of policy easing by the Bank of Japan when it meets on Tuesday.
The dollar was last down 0.8 percent at 79.64 yen. Some strategists said a weekly close above 80 yen would be a strong bullish signal that may prompt further dollar demand.
The greenback, at current prices, was on pace to end the week 0.5 percent higher against the yen, adding to last week's rise of 1.1 percent and helped by widening spreads between two-year U.S. Treasuries and Japanese government bond yields, with which the dollar/yen has a strong correlation.
``Dollar/yen has risen well ahead of itself in the past few weeks and while on a multi-month basis we expect it to rise, there will be some profit taking in the short term to smoothen out the move,'' said George Saravelos, G10 FX strategist at Deutsche Bank.
The BOJ is expected to ease monetary policy at its meeting on Tuesday by expanding asset purchases, and it could make a stronger commitment to keep pumping cash until its 1 percent inflation target is attained.