Access to key components for servicing was also restricted by the car's compact size and transverse-engined layout, the one defect that subsequent evolutions could not fully rectify.

However, Juha Kankkunen's four podium places, coupled with victories on the Olympus Rally and the final round, the RAC Rally, saw him clinch the title ahead of Markku Alén, whose title hopes ended on the RAC with a series of accidents, including overturning the car in front of the television cameras on one of the opening day's short spectator stages.

During 1989 serious challengers to Lancia's dominance began to emerge, including the Toyota Celica GT-Four ST165, which in the hands of Juha Kankkunen had run Markku Alén close on the previous year's 1000 Lakes Rally before retiring with mechanical failure.

By the time guest driver Mikael Ericsson took it to victory on the Rally Argentina, the 8v Integrale had won all of its previous twelve World Championship events.

Having won both the manufacturers’ and drivers’ titles for the third year running, Lancia declined to contest the final round of the season, the RAC Rally.

Markku Alen left the team after nearly fifteen years whilst Juha Kankkunen rejoined, alongside Biasion and Auriol.

However, in the hands of Juha Kankkunen the Delta took wins in Kenya, Argentina, Finland and Australia, and Didier Auriol also won at Sanremo, giving Lancia the manufacturers’ title for a record fifth time.

The Lancia was among the most powerful, which, along with its reliability, accounts partly for its continued success in the face of handicaps such as poor weight distribution (the Delta was always nose-heavy) and a transmission system less sophisticated than that of the Toyota.

In fact the Celica initially proved problematic and Auriol dominated the early part of the season for Lancia, taking a record six wins and pulling out a large championship lead.

Kankkunen also scored consistent podium finishes and a win in Portugal, whilst guest driver Andrea Aghini won the Rallye Sanremo.

For 1993, Auriol and Kankkunen both left Lancia and joined the Toyota team, while Sainz moved to the Jolly Club, where he was supported by Aghini and Gustavo Trelles.

Lancia's sponsorship from Martini also ended, and the Jolly Club Deltas ran in the colours of Sainz's sponsor, oil firm Repsol.

He finished second again at Sanremo, but the team was subsequently disqualified and docked points for fuel irregularities, and Sainz had by then retired from the Catalunya Rally with electrical failure.

Astra continued to run Deltas on European and some World Championship events in 1994, the best result being fourth place for Alessandro Fiorio on the Acropolis Rally.