Or, more to the point on this afternoon, how such a stinging serve and big groundstrokes didn't help her avoid first-round exits each of the past five years at Wimbledon.
When Williams left the game soon after claiming her 23rd Grand Slam at the 2017 Australian Open, it appeared her streak might be under threat.
"It is a great feeling to be in the final and playing on the Centre Court is always a great experience and I am really excited", she told the BBC.
"I didn't expect to play this well so quickly into my comeback", Williams said after the match.
The 36-year-old, who will be in her first final at the majors since giving birth to daughter Olympia last year, can equal Margaret Court's all-time record of 24 Slam titles if she beats Kerber in what will be a repeat of the 2016 final at the All England Club.
"It is a completely new match", said Kerber, who failed to make a Grand Slam quarterfinal in 2017, won zero tournaments, fell from No. 1 to 21 and changed coaches.
Serena Williams dropped the opening set but won against Camila Giorgi.
Kerber, in contrast, bides her time, working the back of the court to get everything back over the net, often kneeling to get low enough to reach shots. Goerges, reduced to hit 13% of her groundstrokes inside the baseline, much less than the average 37% registered in their previous rounds, had to survive a huge, constant pressure from the back and her hopes to play the second all-German major final (Aussem won the only previous one at 1931 Wimbledon over Kranwinkel) faded.
Two-time Grand Slam champion Kerber remained solid amid an onslaught of winners and unforced errors from the more aggressive Ostapenko.
However, the 14 errors meant that Kerber, at the third attempt, broke to lead 4-3.
But she couldn't keep up with Williams, who grabbed 18 of 22 points and five consecutive games to close the first set and begin the next.
The left-handed Kerber was mainly a passive participant in the early going against Ostapenko. Ostapenko's strokes were missing and she grew increasingly frustrated, slapping a thigh after a miss or leaning forward and putting her hands on her knees after others.
Wimbledon continues Friday with the men's semifinals: Rafael Nadal playing Novak Djokovic for a 52nd time, most between two men in the Open Era (Djokovic leads 26-25), and American John Isner against South African Kevin Anderson in a match of first-time Wimbledon semifinalists.