The opening round of the 1990 Hopman Cup took place on Boxing Day with the day match between eighth seed Italy and Sweden. In the opening match, Italian player Paolo Canè struggled in his first single match against Swedish player Mikael Pernfors as he went down in three sets. Italy though would come back in the remaining two rubbers with Cane and Laura Golarsa winning the mixed doubles in straight sets before Golarsa took out the tie. In the night session, fifth seed Australia defeated Yugslavia 3–0 to book their spot in the quarter-finals with straight sets victories for Mark Woodforde and Hana Mandlíková. The second day saw the remaining two matches of the opening round of competition. First was seventh seed, Austria who clean-sweep their tie against New Zealand with Thomas Muster and Barbara Paulus both winning their single matches in straight sets before being pushed to three in the mixed doubles. The final match of the opening round saw the tie between sixth seed, France and the Netherlands lasting seven hours. After Isabelle Demongeot won the women's singles in three singles, the tie headed into a third deciding rubber after the Netherlands pair of Michiel Schapers and Brenda Schultz won the rubber, 6–3, 6–2. After the match, Yannick Noah stated, "I don't know whether I was playing tennis or being a clown." In the deciding rubber, Noah loss the first set, 6–3 and trailed Schapers 5–4 in the second before coming back and winning the remaining two sets in a tiebreaker to book France's spot into the quarters.
Sweden vs. Italy
Yugsolavia vs. Australia
Austria vs. New Zealand
France vs. Netherlands
Quarter-finals
The quarter-finals began on 28 December 1989, with Australia taking on fourth seed, the Soviet Union in the opening match of the quarters. In what would soon be an easy tie, the Australians only dropped seventeen games throughout the three matches to defeat the Soviets 3–0 with Mandlíková and Woodforde securing straight set victories in all of the matches. Before the match against France, Czeechoslovakia player Miloslav Mecir was replaced with 63rd ranked player Petr Korda due to torn ligaments in his ankles due to skiing accident, three weeks prior. In the women's singles, the use of the cross-court play put Demongeot on the wrong side of court as she led the French woman to ten double faults in the three set match. Czechoslovakia took out the title in the mixed doubles with Mecir and Helena Suková winning in three sets. Mecir went on to get the sweep for Czechoslovakia, defeating Noah in straight sets. The brother-sister combination of Arantxa Sánchez Vicario and Emilio Sánchez opened their campaigns with a 2–1 win over the Austrians in their quarter final with the women's match going to three sets while the men's match lasted until 1:30am with Thomas Muster coming outon top in three after conceding the first set in a tiebreaker. Top seeds, United States won their opening tie against Italy 3–0, but the match was notable for John McEnroe clashing with English umpire, Jane Tabor before forfeiting the game for sitting down. He would go on to win the match in three sets.
The first semi-final was Spain and Czechoslovakia on 30 December 1989. In the opening rubber, Emilio Sánchez got the break in the seventh game of the first set but conceded it in the next game with the set going to Sanchez in a tiebreaker. The second set saw only one break of serve with Korda serve being broken to give Spain the lead. After the Spanish conceded the mixed doubles in straight sets, Arantxa Sánchez had trouble with her strained leg muscle putting her one break down in the second set after losing the first 6–3. But words of encouragement from her brother, saw Arantxa win the next two sets in tiebreakers to book Spain a spot in the final. The second semi-final was played the following day and saw the United States take on Australia. For Mark Woodforde, he was never in the match with two breaks off the Woodforde serve giving McEnroe the first set with the second set also going to the American as McEnroe gave the United States a lead. Australia got an early break in the mixed doubles with the McEnroe dropping his serve to give Australia a two-game lead. But two consecutive breaks off the Mandlíková serve gave the United States the first set, 6–4. The second set was a tiebreak which Australia came back from 4–0 to level it five-all before the United States took out the tie. The third match wasn't played due to the withdrawal of Mandlíková due to a back complaint.
Spain vs. Czechoslovakia
United States vs. Australia
Final
The final of the 1990 Hopman Cup was played on 1 January 1990 between Spain and the United States. In the opening rubber, McEnroe got the jump over Emilio Sánchez in the first set winning 7–5. Emilio Sánchez came back to level the rubber, winning the second set with the same scoreline with McEnroe being penalized a point penalty which gave Sanchez the break. From there, the Spaniard went on to win the match in three sets, taking out the final set 7–5. After the Americans took out the mixed doubles in straight sets, the tie went to a deciding third with Arantxa Sánchez taking the match and the title with a straight set victory.
