IIRC, it was posted here, as well as stated during opening day coverage, that Garner commented that Biggio is hitting leadoff because he anticipates RBI opportunities at the tail end of the lineup and he wanted someone who could take advantage of those opportunities.
Willy seemed to bare down during the at-bat where he hit what looked like a bloop single, but the announcers called a "line drive", plating 2 runs. He's definitely hit some balls hard and had nothing to show for it. So if a bloop single got it done, great.
Willy doesn't have to knock the screws off it. If he keeps making contact, along with showing better plate discipline, he's doing his job. Teams were cheating on him, expecting one of his infield hits. He appears to be adjusting to that. I hope he continues to succeed there. If nothing else, he's keeping the defense honest and not being forced into a single dimension type approach at the plate where he's only looking to bunt or scratch out an infield hit.