SAN ANTONIO -- The season-long Charles Schwab Cup race is coming right down to the wire again with the top two players, Jay Haas and Loren Roberts, competing this week in the AT&T Championship presented by Alcatel, the final full-field event of the Champions Tour season.

The winner receives a $1 million annuity in the competition designed to recognize the Tour's leading player. Haas, who won last week’s Administaff Small Business Classic, holds a 156-point lead over Roberts and is up by $137,966 on the money list.

Haas is the defending champion at Oak Hills, where he also won the Texas Open in 1982 and ’93. Roberts is another former Texas Open winner, taking the title in 2002 across town at LaCantera Golf Club.

"I love Oak Hills and have had some good luck there over the years," Haas said. "If I continue to play well, I can be there at the end."

Both Haas and Roberts have won four Champions Tour events this season -- including one major each. They’re eagerly anticipating the race to the finish at Oak Hills starting Friday and in Sonoma next week at the Charles Schwab Cup Championship.

"I'm looking forward to playing a lot and playing well in the month of October," Roberts said. "I think this is the perfect ending to the season. I certainly like Oak Hills and I'm looking forward to playing in the AT&T Championship."

Haas has won four Champions Tour events this season.(Badz/PGA TOUR/WireImage)

Roberts and Haas are the only two Champions Tour golfers who have led the Charles Schwab Cup competition in 2006.

Roberts, who won the first three events of the year, led the initial 11 weeks. Haas took the lead after winning the Senior PGA Championship and led for the next seven weeks before being overtaken by Roberts, after he won the Senior British Open. The lead changed again last week in Houston.

"I think this is great for the Champions Tour and great for the Charles Schwab Cup to see the competition come down to the final weeks, especially at a course and a city we both love," Roberts said.

The Charles Schwab Cup rewards both top finishes and week-in/week-out consistency at all 28 official Charles Schwab Cup events. Points are awarded to the top-10 and ties based on the money distribution for each tournament, with every $1,000 earned being the equivalent of one Charles Schwab Cup point.

Points are doubled at the Champions Tour's five major championships and the season-ending Charles Schwab Cup Championship next week.

Joining Haas and Roberts in San Antonio this week is Fred Funk, who will be playing in his third Champions Tour event. He says Oak Hills Country Club is a worthy site for one of the final Charles Schwab Cup showdowns.

"I played there last month to get ready for the AT&T and I couldn't believe how little it had changed and what a great course it still is," said Funk. "That is such a narrow and challenging course for those players, you almost have to walk single file down the first fairway."

Eight of the top-10 players in the Charles Schwab Cup standings are entered in the AT&T Championship.

"Not only do we have one of the best fields in the 20-plus year history at the AT&T Championship, but we have the two players in one of the tightest ever Charles Schwab Cup races competing at Oak Hills," said AT&T Championship Tournament Director Colby Callaway. "It's going to be quite a show for our fans."