It was on 9 April 2013 that the history of the German city of Dortmund and Malaga became entwined forever. On that day, Málaga CF was on the brink of reaching the semi-finals of the Champions League, but two goals by Borussia - and a controversial decision by the referee - put paid to the Malaga team's European dream. Nearly four years later, the paths of these two cities have crossed again, but in a less competitive manner. The German team is one of the most prestigious of those who have decided to spend their scheduled winter break in Marbella this year.
Nearly 70 teams will be coming to the Costa del Sol, hoping to escape the cold and to keep fit while they have no matches to play, and the hotels are taking advantage of this to overcome their problem of seasonal tourism.
For more than four years now, Football Impact has been managing most of the clubs who decide to come to the Costa del Sol at this time of year, and they say the number of overnight stays by these teams has now reached 46,000.
However, the actual figure is higher than this, because it doesn't take into account the fans who take advantage of their favourite team's visit to also come to the Costa del Sol for a few days.
"The teams want peace and quiet in their hotels, so the fans don't stay in the same places. We didn't expect so many fans to follow Borussia here, though; they are hoping to see the players close-up," explains Oscar Habash, the commercial director of the Gran Meliá Don Pepe hotel, where the German team is staying.
At a time of year when hotels do not have many clients, on Wednesday and Thursday this week two Champions League teams were staying at this hotel. Borussia were joined by FC Basel, the current Swiss champions who lost in the preliminary phase of the most important continental competition.
It was these teams, with their large numbers of players and employees, who booked the most overnight stays in local hotels.
"There are differences between the big and small teams. Normally, the players are made to share rooms, two to a room. However, Borussia prefers everyone to have their own room," says Oscar Habash, who calculates that a big team is likely to book about 600 overnight stays in all.
The difference in the length of stay and the form of accommodation the teams choose can make all the difference. Dutch and German teams normally stay for a week, while Russians, Scandinavians and Chinese tend to stay longer.
In the last three years, the evolution of these visits by football teams to the Costa del Sol has been very positive. In 2014, there were more than 20,000 overnight stays, and now that more teams come and stay longer, this figure has doubled.
The agreements between Football Impact and the hotels mean that some establishments which would once have closed in the winter due to lack of business can now remain open. One of these is the Westin La Quinta, situated between Marbella and Benahavís, which opens just for these team bookings.
In this case, the functioning of the hotel in terms of restaurant service and room cleaning is minimal, because nobody else will be staying there.
This exclusivity is one of the attractions which has encouraged many of the bigger teams to come to the Costa del Sol. The Westin La Quinta has been booked by Inter Milan and Borussia Monchengladbach. Dynamo Kiev arrived recently, and Spartak and Lokomotiv Moscow are expected soon, following a few days at the Kempinski hotel in Estepona. So is Hebei China Fortune, whose trainer is former Malaga coach Manuel Pellegrini.
This year, the presence of these teams on the Costa del Sol has boosted the provincial government's 'Sport Destination' initiative, under which Malaga seeks to encourage sportsmen and women to spend time here.
The presence of these clubs has an economic impact of about 6.5 million euros in the area, including not only the expenditure on hotels but the players' and fans' own spending.
Each footballer spends on average around 1,500 euros during their stay, in addition to the money spent by the fans who come to see them and the foreign residents who are already on the Costa del Sol. These days, tourism in this region is on the increase in the winter months, and it is all thanks to the influence of football.