• Fresh signs of slowing global growth, and emerging pockets of weakness in the U.S., rattled financial markets last week.

• And the sell-off continued Monday, with weaker-than-anticipated data from the U.S., China and Japan adding to mounting worries about the global economic outlook for 2019.

• "We expect the U.S. to slow down to less than 2 percent by the end of next year and as a result of that you could see the market getting quite scared," Christian Mueller-Glissmann, senior multi-asset strategist at Goldman Sachs, told CNBC on Monday.

Global equity markets could struggle to come to terms with a dramatic slowdown from the world's largest economy next year, one Goldman Sachs GSBD strategist told CNBC on Monday, with trade tensions elevating the risk of near-term volatility.

Fresh signs of slowing global growth, and emerging pockets of weakness in the United States , rattled financial markets last week. And the sell-off continued Monday, with weaker-than-anticipated data from the U.S., China and Japan adding to mounting worries about the global economic outlook for 2019.

"Next year is going to be tough because I think one of the key changes to this year is that the U.S. is going to slowdown," Christian Mueller-Glissmann, senior multi-asset strategist at Goldman Sachs, told CNBC's "Squawk Box Europe" on Monday.

"We expect the U.S. to slow down to less than 2 percent by the end of next year and as a result of that you could see the market getting quite scared," Mueller-Glissmann said.

IMF sees no signs of a US recession

U.S. equity futures were seen down 0.3 percent Monday morning, adding to losses from last week that saw the Dow Jones Industrial Average erase its gains for the year. At one point, the Dow was up more than 8 percent for 2018.

On Friday, wage increase figures and jobs data compounded worries over U.S. economic growth for 2019.

Non-farm payrolls last month increased by 155,000 jobs last month, missing analysts' expectations of around 200,000. And the wage increase was also softer-than-expected despite its annual rise hovering close to levels not seen in almost a decade.

Despite relatively weak economic data in the U.S. triggering another wave of selling in financial markets, the managing director of the International Monetary Fund (IMF) said Thursday that she didn't see any cause for alarm .

Speaking to CNBC's Sara Eisen in Washington last week, Christine Lagarde said: "I don't see the elements of a recession in short order… We still have a strong growth forecasts for next year for the U.S."

Trade tensions

Meanwhile, adding to concerns about a possible economic slowdown, market participants are also closely monitoring trade negotiations between Washington and Beijing.

U.S. Trade Representative Robert Lighthizer said Sunday that talks between the two sides must reach a successful end by March 1, following conflicting comments about whether a hard deadline had been agreed.

Stock markets were already reeling amid reports that Canadian officials had arrested the CFO of Chinese telecoms giant Huawei for extradition to the U.S., with the news threatening to derail progress in U.S.-Sino trade talks.

"The problem we have of course is that the trade news flow is still critical in driving near-term volatility and it doesn't feel like you have any stabilization," Goldman Sachs' Mueller-Glissmann said.

"We don't expect a comprehensive trade deal to come out in the very near-term so … I think emerging markets could be quite volatile."

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