(New throughout, updates prices, market activity and comments) * Canadian dollar weakens 0.9% against the greenback * Loonie hits an eight-day low at 1.2729 * Price of U.S. crude settles 3.2% lower * Canadian bond yields fall across a flatter curve By Fergal Smith TORONTO, Feb 26 (Reuters) - The Canadian dollar tumbled against its broadly stronger U.S. counterpart on Friday as this week"s spike in bond yields weighed on investor sentiment, with the loonie extending its pullback from a three-year high the day before. The Canadian dollar was trading 0.9% lower at 1.2710 to the greenback, or 78.68 U.S. cents, its biggest decline since last October. It touched its weakest since Feb. 18 at 1.2729, while it was down 0.8% for the week. On Thursday, the loonie touched its strongest intraday level since February 2018 at 1.2464. "The loonie is losing ground along with other risk assets as market volatility increased on a small tantrum over the rising U.S. yields," said Amo Sahota, director at Klarity FX in San Francisco. The safe-haven U.S. dollar rose against a basket of major currencies and global equity markets swooned, even as the bond selloff eased a bit. Fears of rising inflation still weighed on sentiment as data showed a strong rebound in U.S. consumer spending. "The underlying fundamentals are unchanged so commodity demand strength will remain robust and that should help underpin the loonie and prevent this from turning into a complete rout," Sahota said. Oil prices settled 3.2% lower at $61.50 a barrel as forecasts called for crude supply to rise in response to prices climbing above pre-pandemic levels. Canada"s C$100 billion ($79 billion) stimulus plan is justified by the economic hole caused by the COVID-19 pandemic, government sources said, as analysts warned Ottawa against racking up too much debt and making investments that fail to boost growth. Canadian government bond yields fell across a flatter curve in sympathy with U.S. Treasuries. The 10-year was down 6.8 basis points at 1.398%. On Thursday, it touched a 13-month high at 1.486%, while it was up 18.5 basis points for the week. (Reporting by Fergal Smith; Editing by Steve Orlofsky and David Gregorio)