Since the David and Goliath tale that surrounded its album ''Yankee Hotel Foxtrot," the Chicago band Wilco has continued to mature musically. In a powerhouse two-hour set at Agganis Arena on Friday evening, the sextet proved that its performance chops have grown with a steady consistency matching its studio efforts.
The band took the stage wordlessly and launched into the Woody Guthrie-penned ''Airline to Heaven" that by its conclusion had
reached the hoedown enthusiasm frequently achieved on its earliest rootsy releases. As singer Jeff Tweedy made the move from acoustic guitar to electric for ''I'm the Man Who Loves You" guitarist Nels Cline pushed Tweedy's increasingly noisy leanings.
The additions of Cline and multi-instrumentalist Pat Sansone have wonderfully served Tweedy's vision of a musical form that can incorporate traditional American styles with the more avant-garde leanings of the indie world.
The achingly beautiful ''Sunken Treasure" benefited from Cline's pedal-steel playing, achieving the Western mood of Calexico. The song was followed by the throbbing ''Spiders," and the show hit an immediate high. The Neil Young influence on Tweedy's increasingly impressive guitar playing is pushed further by Cline. At times, particularly when Sansone adds to the guitar din, the result recalls Sonic Youth.
The percussive proficiency of drummer Glenn Kotche allows Wilco to change speeds effortlessly. ''Jesus, etc." was subdued and moody, and paired with the jumping bounce of ''Theologians," the effect was another peak.
This chemistry has seemed to lighten Tweedy's once legendarily heavy mental load. The singer was in fine spirits, introducing ''At Least That's What You Said" as a ''double-homicide singalong" and joking that he could see the crowd moving toward beer and bathroom lines as he was ''singing my heart out on my little poems." He emerged for the encore in a Boston University hockey jersey, and the band recalled one of its singer's earliest heroes with a pretty cover of Bob Dylan's ''I Shall Be Released" that brought the evening full circle.