It has the Tories on 41%, up one point from April, and Labour on 35%, up five.
Smaller parties have seen their ratings slide, with Plaid Cymru down two points to 11%, the Liberal Democrats down one to 7% and UKIP on 4%, down two.
Prof Roger Scully of Cardiff University said the Tory threat to Labour's long-standing dominance was "very real", projecting them to win 20 seats.
A poll in late April suggested Wales was on the "brink of an electoral earthquake" with the increase in Tory support.
Mr Scully said the big change from the last poll, produced by YouGov for ITV Wales and Cardiff University, was "clearly the recovery in Labour support".
"After doing exceptionally badly in the last poll, they have now pulled back within two percentage points of their Welsh vote share in the last general election," he said.
"Yet Labour have not been able to eat into Conservative support at all."
He said the two largest parties "seem to be squeezing the smaller ones".
In April, Mr Scully projected the Conservatives to win a majority of Wales' 40 seats with 21.
The latest projection of 20 seats was still nine more than the Tory haul at the 2015 general election, and would see the Conservatives become the largest Welsh contingent at Westminster.
Labour would have 16 seats, down nine, while Plaid Cymru and the Liberal Democrats would both be unchanged on three seats and one seat respectively.
The online poll, for ITV Cymru Wales and Cardiff University's Wales Governance Centre, had a sample of 1,018 Welsh adults and was carried out by YouGov from 5-7 May 2017.
The Conservatives remain out in front in Wales despite a Labour recovery, a new ITV Wales election poll suggests.