There’s a very real possibility of a second stock market crash in 2020. Risks such as the upcoming US election, Brexit and, of course, coronavirus could cause investor sentiment to weaken.However, a decline in stock prices could present buying opportunities. Through buying high-quality stocks when they trade at discounted prices, it’s possible for long-term investors to generate high returns as the economic outlook improves over the coming years.5G is here – and shares of this ‘sleeping giant’ could be a great way for you to potentially profit!According to one leading industry firm, the 5G boom could create a global industry worth US$12.3 TRILLION out of thin air…And if you click here we’ll show you something that could be key to unlocking 5G’s full potential…High-quality stocksA second stock market crash is likely to be caused by uncertainties surrounding the economy’s future prospects. This could mean the operating conditions for many businesses come under pressure.Therefore, it could be logical for investors to purchase companies with strong balance sheets and access to sufficient liquidity to survive a period of weak sales. They may be better placed to not only still be in existence in a few years’ time, but could also benefit from the demise of their weaker sector peers through increasing their market share.Identifying the strongest businesses in a sector is subjective. However, measures such as debt levels, the amount of cash a company has on its balance sheet, and its ability to access multiple forms of capital should it be required may help you to unearth the best stocks to buy should there be a further market crash.Undervalued stocks in a market crashA market crash can provide an opportunity to buy shares when they trade at low prices. However, this doesn’t mean investors should simply buy the cheapest shares they can find. Many stocks could be cheap because they face difficult outlooks. They may also fail to ultimately recover from their low price levels.As such, it may be prudent to instead focus your capital on those shares that trade at a discount to their intrinsic value. This could mean they aren’t among the cheapest shares around, but that they offer the best value for money based on their quality. It may be more profitable to buy more expensive companies with better prospects, than cheap stocks with difficult outlooks.A long-term strategyIt’s difficult to ascertain when a market crash will end and give way to a sustained bull market. Therefore, while it can offer buying opportunities, there’s a chance of paper losses being sustained in the short run while a stock market fall is taking place.This means that investors should actively adopt a long-term strategy when buying shares in a downturn. History shows that the stock market has always bounced back to post higher highs after even its most severe declines. The same outcome is very likely after this year’s challenges. So this could make it a good time to start building a diverse portfolio of undervalued, high-quality businesses. Click here to claim your copy now — and we’ll tell you the name of this Top US Share… free of charge! Renowned stock-picker Mark Rogers and his analyst team at The Motley Fool UK have named 6 shares that they believe UK investors should consider buying NOW.So if you’re looking for more stock ideas to try and best position your portfolio today, then it might be a good day for you. Because we’re offering a full 33% off your first year of membership to our flagship share-tipping service, backed by our ‘no quibbles’ 30-day subscription fee refund guarantee. Peter Stephens | Tuesday, 18th August, 2020 If a second stock market crash arrives in 2020, I’d follow this plan to capitalise on it I’m sure you’ll agree that’s quite the statement from Motley Fool Co-Founder Tom Gardner.But since our US analyst team first recommended shares in this unique tech stock back in 2016, the value has soared.What’s more, we firmly believe there’s still plenty of upside in its future. In fact, even throughout the current coronavirus crisis, its performance has been beating Wall St expectations.And right now, we’re giving you a chance to discover exactly what has got our analysts all fired up about this niche industry phenomenon, in our FREE special report, A Top US Share From The Motley Fool. Enter Your Email Address “This Stock Could Be Like Buying Amazon in 1997” Image source: Getty Images See all posts by Peter Stephens Our 6 ‘Best Buys Now’ Shares I would like to receive emails from you about product information and offers from The Fool and its business partners. Each of these emails will provide a link to unsubscribe from future emails. More information about how The Fool collects, stores, and handles personal data is available in its Privacy Statement. Simply click below to discover how you can take advantage of this.