MEXICO CITY, MEXICO - OCTOBER 30: Sebastian Vettel of Germany and Ferrari celebrates finishing in third place on the podium during the Formula One Grand Prix of Mexico at Autodromo Hermanos Rodriguez on October 30, 2016 in Mexico City, Mexico. (Photo by Clive Mason/Getty Images)

Sebastian Vettel was once the dominant force in Formula One becoming only the third man in the history of the sport to win four Drivers’ Championships in a row. The German appeared well on his way to challenging Michael Schumacher to be considered the greatest driver in the history of the sport.

However, since his fourth triumph in 2013, Vettel has endured three seasons of underachievement as he has been unable to challenge Mercedes’ dominance at the top. The 29-year-old has been forced to watch Lewis Hamilton stake his claim to be the most successful driver of the era by taking his tally to three Championships.

Vettel watched Hamilton close the gap to Nico Rosberg at the top of the 2016 standings to 19 points when he secured his second consecutive victory by winning the Mexican Grand Prix. The latest Formula 1 news suggests that the Brit could overhaul his Mercedes team-mate and clinch his fourth Drivers' Championship, being backed at 3/1 in the latest odds following his triumph in Mexico City.Vettel meanwhile, was cursing his luck and FIA Formula 1 director Charlie Whiting in an incident involving Max Verstappen on the circuit.

The 29-year-old managed to avoid punishment after apologizing for his outburst, but his poor behavior highlights the frustration that he has felt about being powerless to compete with Hamilton and Rosberg at the top. Daniel Ricciardo has even enjoyed a better season than the German for his old team Red Bull Racing, which will further eat away at the four-time champion.

A poor defence of his crown in 2014 led Vettel to make the decision to switch to Ferrari after he finished fifth in the overall standings. He failed to win a race for the first time since 2008, and only reached the podium four times in 19 races, while issues with his car forced him out entirely in Australia, Monaco and Austria.

The decision appeared to pay dividends when he secured his first victory in over a year at the Malaysian Grand Prix to go with third-place finishes in Australia and China. However, he could not keep pace with the outstanding form of Hamilton, adding victories only at Hungary and Singapore, finishing over 103 points behind the Brit as he claimed the title.

Although Vettel finished behind both Mercedes drivers, he would have been hopeful that he could close the gap in his second season in Ferrari. The 29-year-old has notched five podiums this season, but he has been plagued by issues with his car, none more so than in Bahrain when he was prevented from taking to the grid by an engine failure.

He has endured retirements in Russia, Austria and Malaysia, but his disappointment in Mexico may have pushed the German to the brink of his frustration. Not only was he annoyed by Verstappen’s behavior, but he was then demoted from the podium into fifth place due to a penalty for his own dangerous driving. The German is facing the first crisis point of his distinguished career given how far that his team has fallen behind Mercedes. Should Hamilton clinch his fourth Championship then the pressure will really be on the 29-year-old to match the Brit as he is watching his legacy slip away.

Time is on his side, but he will have to work extremely hard with Ferrari to ensure that he has a car capable of matching Mercedes, while also improving his own skills behind the wheel to make up any difference that there may be between him, Hamilton and Rosberg. Only then may be able to regain his position at the top of the sport, but there is certainly a long road ahead.