The pain has been especially acute in Macau, which is known to attract Chinese gamblers. Macau's gaming revenue declined in June, July, and August after a long string of gains, according to government data.That has caused a sharp selloff in U.S. listed casino companies with major exposure to Macau. Shares of Wynn Resorts have fallen 17 percent in the last six months while Las Vegas Sands has declined 24 percent.
Strong wine sales just might be a sign that Macau's troubles are coming to an end. A recent Deutsche Bank study pointed out that there is a 72 percent correlation between Macau gaming revenue and prices of fine French wine. The link could make sense: Rich Chinese have long had a penchant for French wine such as the famous Bordeaux sold at last weekend's auction.
Some casino moguls remain bullish on Macau. This week, Wynn founder Steve Wynn said he was "not concerned" about the recent slowdown in Macau gaming revenue. "I think the future of Macau is terrific," he was reported to say on Wednesday by the South China Morning Post.
Kapon said that the auction attendees seemed as enthusiastic as ever. "We had a packed room both days," he said. "That's one of the leading indicators—how many people show up."
Read MoreBye bye Bordeaux: The new bull market for wine
In Hong Kong, wine buyers are much more likely to appear in person than in the U.S., Kapon said. "It's much more of a culture where you bid in the room than absentee," he said. "People like the action. It's kind of the gambling mentality that goes out here."
Fine wine has some unique characteristics that may make it more resilient than other markets. For one, people tend to drink what they buy. "Supply of the best stuff is constantly dwindling," Kapon said. "There's probably more strength in the wine market during times of adversity."
Other highlights from last weekend's auction included a rare 12-bottle case of 1978 Domaine de la Romanée-Conti La Tache from France's Burgundy region. The case, which went to an American buyer, tied for the most expensive lot at the auction at a price of $70,000. Kapon pointed out that other Burgundy wines were also snapped up by Chinese buyers, who have branched out from their traditional focus on Bordeaux.
Certain Bordeaux wines remain below their previous peak levels from 2011, when wealthy Chinese buyers helped drive prices to stratospheric levels. While those wines have pulled back, prices of others such as Burgundy wines have continued to grind higher and account for a larger percentage of auction sales.