The Reds and Pirates played before one of the smallest crowds in PNC Park history Thursday, when downtown Pittsburgh was virtually empty because of the G-20 summit.

The paid attendance was 15,892 _ well above PNC Park's all-time low of 8,201 on April 25, 2007, for an Astros-Pirates game _ but the actual turnout was about 3,000.

The turnout was so small that the Pirates closed PNC Park's upper deck for the first time since the 38,362-seat ballpark opened in 2001 and allowed fans to sit in first-level seats.

Crowds for the first two games of the series were unusually low, with Tuesday's crowd estimated at 4,500, but Thursday's audience was especially small because fans were unable to use downtown parking spaces. Most traffic into downtown Pittsburgh was prohibited, and nearly all businesses were dark or told most employees to work from home.

Parking lots near PNC Park were open, but the Pirates said frequent warnings about how difficult it would be to travel into Pittsburgh during the two-day summit clearly kept some spectators away. PNC is located on Pittsburgh's North Side, across the Allegheny River from downtown.

The Pirates, on pace to lose more than 100 games during a record 17th consecutive losing season, trail only Oakland and Florida in attendance despite playing in one of the majors' best ballparks.

Cincinnati won Thursday's game 4-1 to complete its second sweep of the plummeting Pirates in less than a month.

The smallest crowd at PNC Park, in terms of actual turnout, is believed to be the estimated 500 who watched an Astros-Pirates afternoon game on Sept. 28, 2006. The game was delayed by heavy rain for 3 1/2 hours, but was not postponed because the Astros were in playoff contention and had no more scheduled games in Pittsburgh.