SAN FRANCISCO - Many Philadelphia fans still might have a hard time figuring out how the Giants took out the Phillies in six games in last year's National League Championship Series.

As San Francisco returns to Citizens Bank Park Tuesday night for the first time since Game 6 of the NLCS, here's a question to ponder about the 2011 Giants:

How the heck are they 59-43 with a four-game lead in the NL West?

The Giants lost arguably their most important player, catcher Buster Posey, to a season-ending leg injury in late May. They have been without their most consistent hitter, second baseman Freddy Sánchez, since he dislocated his shoulder two weeks after Posey got hurt. Sánchez is probably done for the season.

San Francisco has little power (65 home runs) or speed (63 stolen bases), but the Giants do have pitching, pitching and - for good measure - more pitching. They lead the majors with a 3.08 ERA.

Of course, the Phillies own the best record (64-37) in the bigs. Giants closer Brian Wilson knows how good the Phillies are.

"They're a great team and they got better," Wilson said. "It shows with their record; great pitching. We also have great pitching, too - not as established in the league as those guys might be - but you're going to get good baseball" in this series.

Wilson froze Ryan Howard on a 3-2 slider with two men aboard to end the Giants' 3-2 victory that clinched the NL pennant Oct. 23. With a 6-2 record, 2.83 ERA and 31 saves in 2011, Wilson has the stats to show he's much more than someone with an outsize persona and beard.

Then again, you can make the case that the Giants' two setup men - righthander Sergio Romo and lefthander Javier Lopez - are enjoying better seasons than Wilson's.

Romo (3-1, 1.85 ERA) has shut down righthanded hitters to the tune of 10 for 84 (.119). Lefthanded hitters are 7 for 65 (.108) against Lopez, who's 5-1 with a 2.09 ERA.

Lopez, with his sidearm/submarine delivery, was a key man in last year's NLCS, stifling Chase Utley (0-for-5) and Howard (1-for-5). Counting the postseason, Utley (0-for-10) and Howard (1-for-8) are a combined 1-for-18 lifetime against Lopez.

 Considering this series is a rematch of the NLCS and pits teams that lead their respective divisions, the next three games undoubtedly will receive more attention than your typical late-July series would get.

Former Phillie Aaron Rowand said these games don't carry any extra importance, but they will prove useful as a measuring stick.

"Our intradivision games mean more than anything else," Rowand said. "But obviously, stacking up against the team with the best record in the National League, it's a good test playing against the best competition in the National League."

Notes: Giants outfielder Pat Burrell, who spent nine seasons (2000-08) with the Phillies, is on the disabled list with a foot sprain and will miss the series. Burrell is hitting .233 with seven homers and 21 RBIs. . . . Giants relievers are 22-12 with a 2.86 ERA, 38 saves and a .215 opponents batting average. San Francisco's bullpen leads the majors in wins, saves and opponents average. Only the Padres bullpen has a better ERA (2.82).