How did Red Bull's undercut strategy lead to success at Formula 1's French Grand Prix? At Paul Ricard, Max Verstappen took the lead on the second to last lap from Lewis Hamilton, all thanks to the "powerful" undercut pitstop strategy. But what is an undercut? How did Red Bull pull it off so successfully? And why couldn't Mercedes counter it? Jess McFadyen looks at the French GP and how Formula 1's Undercut strategy lead to Red Bull's third victory in a row.