* TSX ends down 81.51 points, or 0.53 percent, at 15,183.13
* Index edges 0.05 percent higher over the week
* Eight of TSX's 10 main groups trade lower (Adds portfolio manager comment, updates prices to close)
By Alastair Sharp
TORONTO, July 21 (Reuters) - Canada's main stock index fell on Friday as oil price weakness weighed on energy-sector shares and the financial sector added its heft to a broad retreat.
The Toronto Stock Exchange's S&P/TSX composite index lost 81.51 points, or 0.53 percent, to close at 15,183.13. For the week, it edged 0.05 percent higher.
Oil prices slid after a report from consultancy Petro-Logistics predicted higher OPEC production for July, renewing fears of oversupply in the market.
Canadian Natural Resources Ltd shed 2.4 percent to C$37.25, Suncor Energy Inc fell 1 percent to C$38.42, and the energy group retreated 1.4 percent overall.
However, shares of Encana Corp advanced 1.4 percent to C$12.34 after the natural gas producer reported a quarterly profit that topped expectations.
Stubbornly low oil prices have weighed on the commodity-rich Canadian market, making it one of the worst-performing major global indexes so far this year.
Elvis Picardo, a portfolio manager at HollisWealth, a division of Scotia Capital, said energy names are looking attractive from a valuation perspective for long-term investors, while a recent pullback in yield-producing utilities, telecoms and real estate investment trusts provides an opportunity to build a defensive position.
Utilities and telecoms were the only two of the index's 10 main groups to end higher on Friday.
"We think we are probably in the eighth or possibly ninth inning of this global bull market," Picardo said. "Our strategy at this point is one of caution and value orientation."
The TSX's financials group, which accounts for more than a third of the index's weight, lost 0.5 percent. Industrials, an export-dependent sector grappling with a recent appreciation in the Canadian currency, fell 0.7 percent.
Canadian retail sales posted their third healthy increase in a row in May, according to data on Friday, a sign of strength that analysts said boosts the case for another interest rate hike this year despite data showing persistently weak inflation. (Additional reporting by John Tilak; Editing by Meredith Mazzilli and Leslie Adler)