KANSAS CITY, Mo. (AP) — Hunter Pence hit a two-run homer off James Shields in a three-run first that silenced the crowd at Kansas City's first World Series game in 29 years, and the San Francisco Giants led the Royals 3-0 after three innings in Tuesday night's opener.

Kansas City became the first team to start a postseason 8-0 and entered with 11 consecutive postseason wins, one shy of the record set by Yankees from 1927-32 and 1998-99. And the Royals swept the Giants during a three-game series from Aug. 8-10.

But whatever momentum Kansas City had quickly dissipated on a warm autumn evening, and Giants starter Madison Bumgarner extended his Series scoreless streak to 18 innings.

The Game 1 winner has captured 15 of the last 17 titles, a sign of the importance of a quick start.

Following batting practice under a cloudless sky of Royals blue, Shields struggled with his control in the first inning and threw just 18 of 32 pitches for strikes.

Gregor Blanco singled leading off, took second on Joe Panik's flyout and went to third when Buster Posey lined a single to left. Pablo Sandoval pulled a double into the right-field corner that scored Blanco, and third-base coach Tim Flannery sent Posey, who was out by about by 15-20 feet on second baseman Omar Infante's relay of Nori Aoki's throw.

Pence, who had been 0 for 11 in his career against Shields, fouled off a full-count pitch before sending a 93 mph fastball just over the center-field wall despite a wind blowing in.

When Michael Morse singled and Shields fell behind 3-1 in the count to Travis Ishikawa, the Royals had Danny Duffy start to warm up. But Shields recovered to strike out Ishikawa, then yelled into his glove as he walked back the dugout. He allowed five hits in the first inning for the first time since April 2013.

Shields, who got Tampa Bay's only Series win against Philadelphia in 2008, settled down to retire six in a row.

Bumgarner, San Francisco's NLCS MVP, got out of trouble in the third after Infante reached when shortstop Brandon Crawford allowed his grounder to pop out of his glove and Mike Moustakas doubled. Bumgarner struck out Alcides Escobar and Aoki on seven pitches, loaded the bases with a walk to Lorenzo Cain, then retired Eric Hosmer on a bouncer to second.

Following their 23rd NL pennant, the Giants were seeking to add to titles in 2010 and 2012 and become the first NL team to win the Series three times in a five-year span since the 1942-46 St. Louis Cardinals. The revitalized Royals won their third pennant, their first in 29 years, and became the first AL team to hit the fewest big league homers (95) and reach the Series since the 1959 Chicago White Sox.

Each team needed to advance through three rounds of playoffs and create only the second all-wild card Series — the Giants lost to the Angels in seven games in 2002. In an era where a hot fall is paramount, this marked the first World Series in a non-shortened season with no team that won 90 regular-season games.

Kauffman Stadium's 322-foot-wide fountain was bathed in pink lights during pregame introductions, and fireworks exploded above the 105-foot-high scoreboard topped by a gold-colored crown. The Royals host Games 1 and 2 because of the AL's 5-3 win in the All-Star game.

Shields opened with a 93 mph fastball to Blanco, the first World Series pitch in Kansas City since Brett Saberhagen got Andy Van Slyke on a flyout to right fielder Darryl Motley that ended the Royals' 11-0 Game 7 win over the cross-state St. Louis Cardinals in 1985. In a sign of how long ago that was, Kauffman Stadium is among just six current big league ballparks remaining from that year.