Political parties supporting Greece's international bailout will begin forging a government after a victory over leftists staved off the prospect of the debt-laden country leaving the euro and brought relief to global markets.
"The market is going to digest the Greek elections and once the initial euphoria dies down, we will see the market rebalancing and turning their attention to Italy and Spain," said Jim Ritterbusch, president of trading consultancy Ritterbusch & Associates in Galena, Illinois.
"We should see the concerns over Italy and Spain restricting any further upside moves on crude."
Brent crude was up $1.18 at $98.79 a barrel by 0638 GMT, well off a one-week high of $99.50 touched earlier. US oil gained 75 cents to $84.78, after hitting a one-week top of $85.60.
The initial Greek vote results drew expressions of relief from world leaders who are due to kick off a G20 meeting in Mexico on Monday.
But analysts warned the euro bloc leaders would need to act swiftly to present a roadmap towards banking and fiscal union, to ensure adequate bank funding and to contain a crisis, which has already spread from Greece to Ireland, Portugal and Spain and which now threatens Italy, one of the world's biggest sovereign debtors.
The euro zone debt crisis remains among the biggest threats to the global economy and fuel demand.
Analysts said they would be watching China's HSBC flash manufacturing PMI and a Federal Open Market Committee meeting later in the week as these could impact oil markets.
In particular, investors are looking for clues from the Fed for another round of quantitative easing given a recent spate of weak US economic data.
"Monetary policy is not likely to be as effective as it was earlier in the euro crisis," Ric Spooner, chief market analyst for CMC Markets, said in a note to clients.
"However, any moves by the Fed such as an extension of their operation twist program would be supportive for equity markets, increasing the opportunity cost and long run risk of alternative fixed interest investments."