PITTSBURGH — President Barack Obama’s motorcade passed in view of PNC Park in the eighth inning, and military helicopters buzzed over the ballpark all day. Obviously, something big was going on in Pittsburgh.

It wasn’t the Reds-Pirates game, where a deserted ballpark matched the nearly deserted downtown only a bridge length away.

Bronson Arroyo limited Pittsburgh to one run over seven innings and the Cincinnati Reds completed their second sweep of the plummeting Pirates in less than a month, winning 4-1 on Thursday to push the Pirates closer to a 100-loss season.

Joey Votto had a two-run double following Drew Sutton’s RBI double and Brandon Phillips singled for his 95th RBI during a four-run third inning against Charlie Morton (4-9) as the Reds won their eighth in a row against the last-place Pirates. The Reds are 15 games ahead of the Pirates in the NL Central standings after falling behind them for one day following an Aug. 22 loss.

Since then, fourth-place Cincinnati is 21-10 — although it remains one loss away from a ninth consecutive losing season — and Pittsburgh is 5-25. Five losses by the Pirates in their final 11 games would give them 100.

Pittsburgh, long since assured of a record 17th consecutive losing season, has lost six in a row, nine of 10 and 23 of 26 amid the franchise’s worst September spinout since it went 5-22 in September 1998.

At least for the Pirates’ sake, there weren’t many spectators. The paid attendance was 15,892, but the turnstile count was about 3,000 as two bad teams and the G-20 summit held down the turnout. The crowd 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 the lower level.

‘‘It didn’t bother me. I still have to do what I do best, and that goes for the team as well,’’ said Lastings Milledge, whose third homer provided the Pirates’ only run.”

Reds’ boxscore

Thursday’s Game

Reds 4, Pirates 1

Cincinnati Pittsburgh

ab r h bi ab r h bi

Tavers cf 4 1 2 0 AMcCt cf 3 0 0 0

Sutton ss 3 1 1 1 DlwYn 2b 4 0 0 0

Janish ss 0 0 0 0 GJones 1b 3 0 1 0

Votto 1b 4 1 1 2 Milledg lf 4 1 1 1

BPhllps 2b 4 0 2 1 Moss rf 4 0 1 0

Rolen 3b 4 0 0 0 AnLRc 3b 3 0 1 0

Gomes rf 3 0 0 0 SJcksn p 0 0 0 0

Bruce rf 1 0 0 0 Doumit ph 1 0 1 0

Balentn lf 3 0 1 0 Jarmll c 4 0 1 0

Hanign c 2 0 0 0 L.Cruz ss 3 0 1 0

Arroyo p 2 1 0 0 Morton p 1 0 0 0

JFrncs ph 1 0 0 0 NWalkr 3b 1 0 0 0

Masset p 0 0 0 0

Corder p 0 0 0 0

Totals 31 4 7 4 Totals 31 1 7 1

Cincinnati 004 000 000 — 4

Pittsburgh 000 000 100 — 1

DP—Cincinnati 2, Pittsburgh 3. LOB—Cincinnati 2, Pittsburgh 6. 2B—Sutton (4), Votto (32), An.LaRoche (22). HR—Milledge (3). S—Morton.

IP H R ER BB SO

Cincinnati

Arroyo W,14-13 7 5 1 1 1 4

Masset H,19 1 0 0 0 0 2

Cordero S,39-43 1 2 0 0 1 1

Pittsburgh

Morton L,4-9 7 6 4 4 2 3

S.Jackson 2 1 0 0 0 3

Umpires—Home, Todd Tichenor; First, James Hoye; Second, Tim Tschida; Third, Bob Davidson. T—2:40. A—15,892 (38,362).