The American's eighth tournament win this year means that he can no longer be overhauled by Jim Courier, his compatriot and the world No 2, in next week's season- ending ATP Tour finals in Frankfurt.
Sampras, the Wimbledon and US Open champion, lost only one set during the tournament and had few problems against the unseeded Swede, ranked 19th in the world, in a final lasting only 53 minutes.
Despite the defeat, Gustafsson, who had accounted for the highly ranked Germans, Boris Becker and Michael Stich, in earlier rounds, ended his season on a high note.
However, Sampras gave him few opportunities, racing through the first set in 18 minutes. In the second Gustafsson had only one chance to recover, but the American saved two break points at 4-3 up.
'It's been an unbelievable year,' Sampras said. 'My tennis has gotten better and better and I've won the two biggest Grand Slams.
'Throughout the match I felt I was pretty much in control. I never really allowed him to get into his rhythm,'.
Asked whether he could still improve, he added: 'My concentration can still be a bit up and down and my return of serve can improve. The goal coming into my European swing was to stay No 1 for the rest of year. Now it's a goal that will stay with me a lot of years.'
Gustafsson's 7-6, 6-3 semi-final win over Becker meant that the former Wimbledon champion will not be defending his title in Frankfurt. Becker had needed to win in Antwerp to get the necessary points to reach the eight-man event. The final place now goes to the Croat, Goran Ivanisevic, at Cedric Pioline's expense after the Frenchman had lost in the semi-finals to Sampras.
Steffi Graf lost for the first time in seven tournaments when she was beaten 6-3, 6-3 by Conchita Martinez in the final of the Philadelphia women's tournament yesterday. The win ended a nine-match losing streak for the Spanish player against Germany's world's No 1, who underwent foot surgery last month.
ATP CHAMPIONSHIP GROUPS (Frankfurt): Group A: P Sampras (US), S Bruguera (Sp), S Edberg (Swe), G Ivanisevic (Croa). Group B: J Courier (US), M Stich (Ger), A Medvedev (Ukr), M Chang (US). Replacement: T Muster (Aut).Reuse content