The Libertadores Cup holders are expected to face European champions Barcelona in the final, barring the unthinkable in Barca's semi-final against Qatar's Al Sadd on Thursday.
"We attacked with real purpose today and took our chances well," Santos coach Muricy Ramalho told reporters after the Brazilians saw off Reysol with three impressive goals.
"We have good skill throughout the team and finishing ability, which was the difference between the teams tonight.
"There was no luck about the win and the goals were no surprise to me - Neymar, Borges and Danilo always score these kind of goals."
Neymar, coveted by a host of top European clubs, struck fear into Reysol every time he touched the ball and he hit the post after five minutes.
The 19-year-old pin-up with the blond, mohican haircut put Santos ahead after 19 minutes, curling a fabulous shot into the top corner after deftly switching the ball from right to left.
Santos, crowned South American champions in June for the third time in almost 50 years after Pele led them to back-to-back titles, looked capable of scoring at will early on.
Neymar's strike partner Borges smashed home a second goal from the edge of the box in the 24th minute as Santos flexed their muscles and the floodgates threatened to burst open.
Defender Hiroki Sakai threw Reysol a lifeline with a powerful header nine minutes into the second half, until Danilo bent a breathtaking free kick around the wall in the 63rd minute to slam the door on the J-League title holders.
Substitute Ibson rattled the crossbar as classy Santos came close to a deserved fourth goal, roared on by a large section of noisy supporters among the crowd of 30,000.
"We've played three matches in eight days," said Kashiwa coach Nelsinho, sacked by Santos in 2005. "We created chances but paid for not taking them."
On such form, Santos will be hard to beat, even by Barcelona, who are chasing a second Club World Cup title in three years.
Barcelona's semi-final against Asian champions Al Sadd and Sunday's championship match both take place in Yokohama.
