He reached two ATP finals in 1984 and began 1985 by beating Jimmy Connors in the semi final at Philadelphia, before losing to World No. 1 John McEnroe in the final. He won his first ATP singles title in Rotterdam later that year, and ended 1985 ranked just outside the world's top 10.
He consolidated his position as a world class player in 1986, beating rising Stefan Edberg in straight sets at Wimbledon, before losing to defending champion Boris Becker in the quarter finals. He reached his first Grand Slam final at the US Open later that year, where he faced fellow Czechoslovakian, defending champion and World No. 1 Ivan Lendl. The 1986 U.S. Open was notable for the fact that four players from Czechoslovakia competed in the two singles finals for men and women - Mečíř and Lendl, Helena Suková and Martina Navrátilová. Lendl won the match in straight sets 6–4, 6–2, 6–0. Mečíř's 1986 U.S. Open final appearance was the last major final to see a player still using a wooden racket.
Mečíř improved further in 1987, winning six singles and six doubles titles. He met Lendl again in three high profile matches that year, winning the final of the Lipton International Players Championships in Key Biscayne, Florida, while Lendl won the final of the German Open in Hamburg and the semi-finals of the French Open.
By this time, Mečíř's sedate playing style was known to frustrate a lot of the more powerful top ranked players. The Swedish players, in particular, were said to dislike playing against him.
Mečíř was on top form at Wimbledon in 1988, where he defeated Mats Wilander in the quarter-final. It was Wilander's only Grand Slam singles defeat of the year (he won the 1988 Australian Open, French Open and US Open) yet Mečíř beat him 6–3 6–1 6–3, entertaining the Wimbledon crowd with extraordinary displays of stroke making. Commentating on the match for the BBC, John Barrett noted that "The mental battle is certainly today being won by Mečíř - Wilander really doesn't know what to do". He took a two-set lead in the semi-final against Edberg with a similar display, and later led by a break of serve in the final set, but Edberg eventually wore him down on the way to his first Wimbledon crown.
The highlight of Mečíř's career came later in 1988 when he was selected to represent Czechoslovakia in the Seoul Olympics. In the men's singles semi-finals he exacted revenge over Wimbledon champion Edberg, in an exciting five-set match 3–6, 6–0, 1–6, 6–4, 6–2. He then met Tim Mayotte of the U.S. in the men's singles final and won in four sets 3–6, 6–2, 6–4, 6–2 to claim the Gold Medal. He also won a Bronze medal in the men's doubles, partnering Milan Šrejber.
In 1989, Mečíř reached his second Grand Slam final at the Australian Open in Melbourne. Again he came up against Lendl and lost in straight sets 6–2, 6–2, 6–2. It was a tactical victory for Lendl, whose win saw him to reclaim the World No. 1 ranking from Wilander. After the match, Lendl apologized to the crowd, explaining that he and coach Tony Roche had decided the best tactic against Mečíř was to hit shots deep and down the centre of the court, denying his opponent the angles he thrived on.
During his career, Mečíř won 11 singles titles and 9 doubles titles. His career-high world ranking in both singles and doubles was World No. 4. His total career prize money earnings was US$2,632,538. His final career singles title came in 1989 at Indian Wells. His last doubles title was also won in 1989 in Rotterdam.
By the end of the 1989 season, Mečíř was suffering from a back injury and retired in 1990, aged just 26.
Many top players used to cite Mečíř as the one player they most enjoyed watching because of his beautifully simple style and touch. Interestingly, he was known as the "Swede Killer" for the success that he had against Swedish players, especially Mats Wilander.
|Year||Championship||Opponent in Final||Score in Final|
|1986||U.S. Open||Ivan Lendl||4–6, 2–6, 0–6|
|1989||Australian Open||Ivan Lendl||2–6, 2–6, 2–6|
|No.||Date||Tournament||Surface||Opponent in the final||Score|
|1.||18 March, 1985||Rotterdam, Netherlands||Carpet||Jakob Hlasek||6–1, 6–2|
|2.||29 April, 1985||Hamburg, Germany||Clay||Henrik Sundstrom||6–4, 6–1, 6–4|
|3.||4 April, 1986||Kitzbuhel, Austria||Clay||Andres Gomez||6–4, 4–6, 6–1, 2–6, 6–3|
|4.||4 August, 1986||Auckland, New Zealand||Hard||Michiel Schapers||6–2, 6–3, 6–4|
|5.||26 January, 1987||Sydney, Australia||Hard||Peter Doohan||6–2, 6–4|
|6.||23 February, 1987||Miami, USA||Hard||Ivan Lendl||7–5, 6–2, 7–5|
|7.||7 April, 1987||Dallas, USA – WCT Finals||Carpet||John McEnroe||6–0, 3–6, 6–2, 6–2|
|8.||13 July, 1987||Stuttgart, Germany||Clay||Jan Gunnarsson||6–0, 6–2|
|9.||27 July, 1987||Hilversum, Netherlands||Clay||Guillermo Pérez Roldán||6–4, 1–6, 6–3, 6–2|
|10.||20 September, 1988||Seoul Olympics, South Korea||Hard||Tim Mayotte||3–6 6–2 6–4 6–2|
|11.||13 March, 1989||Indian Wells, USA||Hard||Yannick Noah||3–6, 2–6, 6–1, 6–2, 6–3|