Ihsanoglu has been endorsed by around a dozen political parties including the main opposition Republican Peoples' Party (CHP) and the third largest political party, Nationalist Movement Party (MHP) , which is not well-known in Turkey.
The opposition candidate has been trying to make inroads in the election campaign through town-hall meetings, TV appearances and advertisement campaigning.
Some seven percent said they will vote for Kurdish candidate Selahattin Demirtas who many believe doesn't have a real shot at the presidency. TURNOUT AND UNDECIDED VOTERS ARE KEY
Undecided voters and reluctant voters are the key to winning the ticket. Some 12 percent of voters said they will not vote at all, in addition to 6.3 percent of the voters who say they have no idea who they will vote for.
"The gap between Erdogan and Ihsanoglu seems far too wide, and the high number of undecided voters has caused concern within the opposition camp, raising fears of a low turnout," he said.
If Erdogan wins in the first round with less than 55 percent, he would have difficulty in controlling the ruling Justice and Development Party (AKP) government. He needs to get more than 55 percent to claim a strong presidency.
In the first round of elections to be held on Aug. 10, a candidate must win by a count of at least 50-plus-one votes. In the second round, scheduled for Aug. 24, this threshold is not required. ERDOGAN SUFFERS SETBACKS
But Erdogan's image as strong leader in Turkey has been tarnished recently by the graft scanda. Four ministers in his government were forced to resign and a parliamentary investigation commission was set up to probe claims.
He also suffered a setback last year with wide spread anti- government protests in Turkey.
Both corruption and anti-government protests shaved off seven percentage points from Erdogan government's popularity in the local elections held at the end of March.
Turkish citizens living abroad have already started casting votes in the presidential elections. Yet the number of people who scheduled for an appointment to cast a vote remains far below the expectations.
Only 15 percent registered in Germany, home to largest expat population in Europe out of some 2.8 million eligible Turkish voters. The situation in France and Netherlands are also similar.
But the low turnout may hurt Erdogan who is expected to score big among expat voters. TURKS ARE POLARIZED
Erdogan's harsh discourse against the opposition parties, non- governmental organizations and independent media has stirred concerns that he intentionally divides Turks to consolidate his ranks.
The Pew Research Center poll recently found that Turks evenly split on Erdogan, with 48 percent saying he has a good influence on the country and the same percentage saying he has a bad one.