GSTAAD, Switzerland: Juan Monaco held his nerve in a tight final set to upset third seed Guillermo Garcia-Lopez 6-2, 2-6, 6-4 on Wednesday for a second consecutive place in a quarter-final at the Swiss Open.

The Argentine, whose ranking has dropped to 105, won his sixth of eight meetings with Garcia-Lopez, whom he also beat in the second round in Gstaad a year ago.

The unseeded South American missed his first chance to serve out victory in the concluding set but came through into the last eight on his second opportunity two games later, going through on his second match point.

A year ago, Monaco held a match point in his quarter-final against eventual Gstaad champion and current top seeded Mikhail Youzhny.

“I like Gstaad, last year I played a great match against the champion. We both deserved to win it. I was happy with conditions (at 1,010-meter altitude) and I’m back again.

“This year, I’m feeling great. I was a little nervous when I was serving for the match at 5-2. I missed that opportunity. But I just tried to get focused on the changeover, thinking of where I’m going to serve.

“I had to play relaxed, it’s the only way to play a good game. The last game was difficult but I’m m happy with how I played today.

“Every match for me is very important at this moment,” said the player who has reached his third quarter-final of the season.

Monaco stood 23rd on the ATP in early 2011 and won four titles — three on clay — in 2012. His last trophy came the week before the 2013 French Open in Duesseldorf.

He stands outside the top 100 for the first time in more than eight years.

Argentine fifth seed Federico Delbonis was also sent packing by Brazil’s Thomaz Bellucci as the two-time former champion advanced 6-4, 6-4.

Second seed Marcel Granollers fared far better though with a comprehensive 6-1, 6-4 defeat of Swiss wild card Yann Marti while Spain’s Pablo Andujar beat Slovenian Blaz Rola 6-3, 6-3.

In a first-round match interrupted by darkness on Tuesday, Swiss wild card Henri Laaksonen defeated Gianni Mina of France 7-6 (7/5), 7-6 (7/3).

Sock advances in Atlanta Open

In Atlanta, rising US talent Jack Sock eased past Colombian Alejandro Gonzalez 6-2, 6-4 but Uzbek Denis Istomin put a dent in the large home field in the first round of the Atlanta Open on Tuesday.

On a day for the local contenders, 21-year-old Sock, who teamed up with Canadian Vasek Pospisil to win a surprise Wimbledon doubles crown earlier this month, underlined his promise by swatting aside Gonzalez in just over an hour.

Ranked fourth in the US men’s pecking order behind world number 12 John Isner, Sam Querrey (61) and Steve Johnson (64), Sock has carried his stellar doubles form into singles in recent weeks, reaching the last four at the Newport International.

Sock’s quarter-final upset of Isner at Newport shot his ranking to a career-high 69, three places above his current 72, and the highly-fancied Nebraskan will be eager to maintain his form ahead of next month’s US Open.

Americans Robby Ginepri and Tim Smyczek advanced, but sixth seed Istomin was too strong for Rajeev Ram, winning 6-1, 6-4.

The 27-year-old Uzbek number one has yet to crack a maiden ATP title, though has come close in America, reaching the final at San Jose and New Haven in years past.

“I’d like to get that first title and I’d like to get it here,” he told reporters.

The Atlanta Open is the start of the US Open Series, a set of tournaments that are a prelude to the year’s final grand slam starting on Aug. 25.

In other first round action, hotheaded Australian Marinko Matosevic topped Dominican Republic’s Victor Estrella Burgos 6-0, 6-2.