Mäkinen claimed his first win as early as in the second rally, Rally Sweden, followed by Burns who achieved his long-held wish of taking his first WRC victory in the third event, the Safari Rally. The fifth round, Rally Catalunya (Spain) saw the debut of the new Group A specification LANCER EVOLUTION V, which was released in January of that year. Its main enhancement was a wider track. While the maximum width allowed by the WR car regulations was set to 1770 mm, the Group A LANCER EVOLUTION IV had a width of 1690 mm. The 80mm track width difference to the WR cars was turning out to be a benefit in terms of stability, especially at high speed. However, since the entire width of the body had to comply with a mass production model under Group A regulations, MITSUBISHI MOTORS started with expanding the standard production model overall width to 1770 mm. Thus the wider body LANCER EVOLUTION entered the scene.

Mäkinen, who had finished third in the LANCER EVOLUTION V’s first rally, won the seventh round, Rally Argentina, for the third year in a row. Meanwhile, the development of suspension and the electromagnetic active differential with increased center differential clutch capacity was progressing. At the end of the season, the team climbed to the top of the Championship rankings after sweeping three consecutive wins in the Rally Finland, Rally Sanremo and Rally Australia. In the final rally, Rally of Great Britain, Mäkinen had an accident early in the first leg. Oil was dropped by a car participating in the historic car rally, causing Mäkinen to spin and hit a concrete block that destroyed the right rear suspension. Mäkinen was forced to retire. However, Toyota's Carlos Sainz, who was aiming for the Drivers' title, blew his engine just before the final stage’s finish line. It was a thrilling outcome for Mäkinen who won his third consecutive Drivers' title. With Burns winning the rally, MITSUBISHI MOTORS clinched their first Manufacturers' championship title and totaled a staggering seven wins thus achieving a victory ratio of 50% in the season. LANCER EVOLUTION drivers’ dominance continued in the Group N Cup, which Gustavo Trelles won for the third year in a row. This offered MITSUBISHI MOTORS a triple crown, 1998 turned out to be their record-breaking year.