San Antonio, TX (Sports Network) - Meghan Stasi stayed alive with an improbable comeback on Tuesday, while defending champ Ellen Port was knocked out of the U.S. Women's Mid-Amateur Championship.

Stasi, who won this event in 2010, rallied from five down with six to play to down Lynne Cowan in 21 holes in Tuesday's second round, then ousted Kelley Nittoli, 2-up, later in the day to reach the quarterfinals.

Port, a 4-time winner at this championship, defeated Janet Moore in the second round but fell to Christina Proteau, 3 & 1, in the third. Proteau advanced to face Laura Coble -- a 2 & 1 third-round winner over Amber Marsh Elliott.

Corey Weworski moved on by defeating stroke-play medalist Dawn Woodard in the second round and Mina Hardin, 4 & 3, in the third. Weworski, the 2004 winner of this event, will meet Liz Waynick, who outlasted Stefi Markovich, 1-up, in 21 holes to move on.

Also advancing Tuesday was Debbie Adams, who ousted Wendi Golden, 3 & 2, to set up a quarterfinal date with Stacy Dennis -- a 1-up victor over Tobi Herron.

Stasi trailed Cowan by five when, starting at No. 13, she won four consecutive holes to claw her way back into the match. Stasi forced extra holes with a par on the last, then drained a 4-foot par putt on the third playoff hole to advance.

In the quarterfinals, Stasi will take on Andrea Kraus, who got past Tara Fleming, 3 & 1.

The quarterfinals and semifinals will be on Wednesday before Thursday's 18- hole final.

The Sports Network