By sportswriter Michael Butterworth

BEIJING, Aug. 28 (Xinhua) -- Formula 1 purists of the world over were left disappointed earlier this month, when Fernando Alonso announced that he would make a full-time switch to the US-based IndyCar Series for 2019.

Having made a guest appearance at the 2017 Indy 500, in which he ran competitively before retiring with engine failure, the two-time Formula 1 world champion will be hoping to once again be in a position to fight for race wins on a regular basis next year. If the Spaniard does prove a hit across the pond, he wouldn't be the first driver to have tasted success in both Formula 1 and IndyCars. Xinhua takes a look at five drivers to have raced at the sharp end of the world's two leading open-wheel racing categories.

1. Mario Andretti

A bona-fide motorsport legend, Italian-born Andretti is one of the most celebrated drivers in history, whose name has become a byword for speed in his adopted homeland of the United States. The Pennsylvania resident won Indycar titles in 1965, 1966 and 1969 and also scooped an Indy 500 win, before switching full-time to F1 and winning the 1978 World Championship with Colin Chapman's revolutionary Lotus 79. Andretti then returned to the Indycar series in 1982 and raced with distinction for another 12 years, finally bowing out of single seaters at the ripe old age of 54. Known for his versatility as well as the length of his career, Andretti also successfully tried his hand at several other forms of motorsport, winning races in stock cars, sports cars, midget cars and sprint cars, and remains the only person to have won motor races of any kind across five different decades. Though Mario is long since retired, the Andretti name lives on in motorsport through his son Michael and grandson Marco, both successful racers in their own right.

2. Emerson Fittipaldi

One of the first Brazilians to race regularly in Formula 1, Fittipaldi shot to prominence in 1970, winning that year's Italian Grand Prix for Team Lotus in only his fifth F1 start. Quickly establishing himself as team leader, the Brazilian won the 1972 F1 World Championship, before repeating the trick driving for McLaren in 1974. Fittipaldi's F1 career then nosedived somewhat, as he made the brave but ultimately foolhardy decision to join his brother Wilson's team, wasting several years in uncompetitive cars before quietly bowing out of the sport in 1980. After a few years out of the cockpit, Fittipaldi arrived on the Indycar scene in 1984 and soon proved he had lost none of his speed, winning the series title in 1989 and also scooping two Indy 500 wins. The Brazilian continued to race with distinction until a nasty crash in 1996 brought about his abrupt retirement from racing at the age of 49. Like Andretti, Fittipaldi also started something of a family racing dynasty, with nephew Christian and grandsons Pietro and Enzo also currently racing professionally.

3. Nigel Mansell

Making his F1 debut in 1980, Mansell soon attracted hordes of adoring fans enthralled by his aggressive driving style and his never-say-die attitude. After coming agonizingly close to the F1 title on three separate occasions, "Our Nige" finally got the job done in 1992 at the wheel of the all-conquering Williams FW14B. But Mansell was not to defend the title he had waited so long to win, as a contract dispute saw him decide to retire from F1 at the end of the season. Instead, the Briton pitched up on the Indycar grid for 1993, driving for the crack Newman/Haas Lola team. Having joined the series to considerable fanfare and huge media attention, Mansell did not disappoint, becoming the first Indycar driver to win on his first start, before adding another four wins to become the series' first ever rookie champion. The Englishman's form tailed off the following year, and before 1994 was out he was back in F1, winning the Australian Grand Prix as a late-season replacement for David Coulthard in the Williams. This led to a full-time ride with McLaren for 1995, but after a multitude of problems for both driver and car, Mansell decided to call it quits after just two races with the Woking outfit.

4. Jacques Villeneuve

Son of the legendary Gilles, Jacques' single-seater career took off after he graduated to the IndyCar series in 1994, winning that year's Rookie of the Year award. Things got even better for the Canadian in 1995, as he won the Indy 500 on the way to taking that year's IndyCar series title. With his stock at its highest, Williams saw fit to sign Villeneuve up for their F1 team for 1996, and the Canadian lived up to his billing, taking pole position and leading on his first start before engine problems saw him ultimately give best to teammate Damon Hill. And although Hill was to pip him to that year's World Championship, Villeneuve would not be denied in 1997, edging Michael Schumacher after the latter attempted to ram him off the road at the final race in Jerez. That would be as good as it got for Villeneuve in F1 however, as a series of poor career moves saw him slip further down the grid before abruptly leaving the sport halfway through 2006. Since then, the Canadian has tried his hand at just about every other form of motorsport, including sports cars, NASCAR, V8 Supercars, Formula E and even Rallycross.

5. Juan Pablo Montoya

After cutting his teeth in single seaters in the UK, Montoya moved over to America in 1999 and took the IndyCar series by storm, becoming only the second driver after Nigel Mansell to win the championship in his rookie year. A debut Indy 500 win followed in 2000, and Montoya agreed to switch to F1 with Williams in 2001. The upstart Colombian soon ruffled more than a few feathers, barging past Michael Schumacher to lead only his third race, and he duly claimed his first Grand Prix win later that year. Growing frustrated at Williams' inability to provide him with a championship-winning package, the Colombian moved to McLaren for 2005. However, a combination of a slow start and some questionable off-track excursions put paid to a sustained title challenge, and Montoya surprised many by swapping F1 for NASCAR halfway through 2006, staying in that series for nine years before returning to IndyCars. Showing he had lost none of his pace, the Bogota native won his second Indy 500 in 2015 and came within one point of winning that year's IndyCar series title. Still very much an active driver, Montoya currently races in sports cars, and finished third in his class at this year's 24 Hours of Le Mans.