TORONTO (Reuters) - Toronto's key stock index ended at its lowest closing level in five years on Friday, as early strength credited to a better-than-expected US jobs report faded, replaced by fears about the severity of the economic downturn.

The index, which fell as much as two percent to its lowest intraday level since October, 2003, pared much of its losses late in the session, as higher oil prices helped boost energy shares.

But the rebound fell short and left the index just below the break-even level for the day as weakness in the technology, financial and materials sectors combined to more than offset the energy rally.

BlackBerry maker Research In Motion, one of the key drags on the index, ended down 4.55 percent at C$46.60, insurer Manulife Financial fell 3.5 percent to C$9.65, and gold producer Goldcorp skidded 1.6 percent to C$37.82.

"We saw strength earlier in the day but it's been a familiar pattern where if you see some strength, the selling invariably starts and markets again trend lower," said Elvis Picardo, analyst and strategist at Global Securities in Vancouver.

"The big driver today was US jobless numbers and at some points it seemed like the markets were taking that in stride, but that didn't last very long."

The U.S. data showed 651,000 jobs lost in February, a huge number but fewer than some analysts had expected. Yet as the session wore on the data served as a reminder of the dire economic situation in Canada's largest trading partner.

The S&P/TSX composite index closed down 37.70 points, or 0.49 percent, at 7,591.47. On the week it was down 6.3 percent.

The market rallied early in the session, with the index up as much as 1.77 percent. It later fell to a five-year low of 7,479.96.

Eight of the TSX's 10 sectors ended the session lower.

A more than four-percent rise in the price of oil, a key Canadian export, helped the energy sector to a gain of 1.26 percent, by far the best-performing sector in the session.

Suncor Energy shares rallied 4.39 percent to C$27.35, while Canadian Natural Resources ended up 3.18 percent at C$41.80.

The TSX's only higher close during the past week came on Wednesday, but the two-percent rally did not carry over into the next session, when it eventually relinquished all the gains.

"The decline over the past five days has been pretty staggering...there's just continued bearishness and that theme hasn't changed," said Mr. Picardo. "It's very hard to make a sustainable sort of advance given the level of pessimism."