Ivan Lendl beat Jim Courier, 6-2, 6-3, to go 2-0 in the event and virtually assure a spot in the last four. Courier, the top seed and the No. 2 in the world, dropped to 1-1.
Guy Forget beat Karel Novacek, 6-3, 7-6 (7-3), to maintain his chances of reaching the semifinals.
The $2.25 million year-end event pits the top eight players in the world. They are split into two groups, with the top two in each group advancing to the semifinals.
Forget, Novacek, Courier and Lendl are in one group; Stich, Sampras, Andre Agassi and Boris Becker are in the other. Agassi and Becker were idle yesterday. On Tuesday, Agassi beat Becker, 6-3, 7-5.
Stich will play Becker today for a place in the semifinals. Also today, Agassi will meet Sampras and Lendl will face Novacek.
Sampras posted an impressive victory in his first career match against Stich.
The American, now 1-0 in the event, broke Stich in the fourth game and again in the eighth, at love, to win the first set in 29 minutes.
Courier, the French Open champion, hadn't won a set against Lendl in three previous career losses and didn't look close to winning one this time.
Lendl, making his 12th appearance in the year-end event that he has won five times, was all over Courier with his powerful all-court game. He broke for a 3-2 lead to set the pattern.
A volley by Courier that sailed long gave Lendl the match in 80 minutes.