Lam entered the venue side-by-side with Xi, smiling and chatting with the president while her Macau counterpart, Fernando Chui Sai-on, followed together with Vice-Premier Han Zheng.

Lam’s entrance raised eyebrows among those who saw it as a departure from protocol for her to walk in front of top mainland officials, but she later advised the media not to read too much into it. She suggested it had more to do with chivalry as she was the only woman among the officiating guests.

Among those with front-row seats at the ceremony were: Vice-Premier Liu He, Xi’s point man on economic policy; Ding Xuexiang, a trusted aide; Guangdong party boss Li Xi; former Hong Kong leaders Leung Chun-ying and Tung Chee-hwa; and Macau’s chief executive.

The mega bridge, which puts the three cities it links within an hour’s drive of one another, is slated to further integrate the two special administrative regions with southern China and boost business, but critics have called it a “white elephant”, doubting if it was worth the HK$120 billion (US$15.4 billion) Hong Kong invested in it.

While Xi did not make a speech at the 30-minute ceremony, except to declare the opening of the bridge, the official Xinhua news agency quoted him as saying it demonstrated China’s fighting spirit.

The mega project also reflected China’s power and ambition, as well as innovation, Xi was quoted as saying at the event, which marked his first trip to Guangdong since 2012, when he visited the province soon after coming to power.

He described the project as a bridge of “fulfilled dreams”, “connected hearts”, “confidence” and “rejuvenation”.

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A structure of such scale needed to be built and maintained well, Xi added, so that it would help with the Greater Bay Area project to develop a technology-led economic hub comprising Hong Kong, Macau and nine mainland Chinese cities.

After the ceremony, Xi was taken on a tour of the bridge with a select group of guests. They met with the builders and told them they should be proud of what they had accomplished.

Upon returning to Hong Kong, Lam said Xi was concerned about the city’s readiness to get on board the Greater Bay Area initiative, and had asked about the local airport’s capacity to handle a heavier load as a result of greater integration.

Lam said Xi was “glad” to know that Hong Kong was building a third airport runway.

Asked about her entrance with the president, Lam replied: “I did not read too much into that. As you may have noticed, I was the only woman among the officiating guests. Throughout the ceremony – including a short meeting – the others were very nice to me, including the two vice-premiers. They told me to sit closer and walk closer.”

At the ceremony, Lam said that Hong Kong had both played a part in and benefited from China’s reform and opening up to the world, which began 40 years ago.

Lam also brought up her “Lantau Tomorrow Vision”, a controversial reclamation-driven project to build a new metropolis to tackle the city’s housing shortage. With the new bridge and Hong Kong International Airport nearby, Lam said, Lantau Island would become a “double gateway” to the world and the bay area.

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“The Greater Bay Area was plotted and planned personally by President Xi Jinping. It is an important national strategy which he personally pushed for. It provides important opportunities for Guangdong, Hong Kong and Macau,” Li said.

Han, Beijing’s man in charge of regional economic integration, said: “[The bridge] opens up all three places for greater exchanges in economics and trade … It also enhances the competitiveness of the Pearl River Delta.”

Construction started in 2009, and the bridge was originally due to open in 2016.

China watcher Bruce Lui Ping-kuen said Hong Kong’s importance in Beijing’s eyes was highlighted in the ceremony arrangement, which might also signify the central government’s support for Lam and its wish for her to seek a second term.

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Liberal Party leader Felix Chung Kwok-pan, who attended the ceremony, said: “Under the normal arrangement, officials walk in according to their ranking … that shows Hong Kong is ranked at the very top in Beijing’s eyes.”

Not everyone was excited about the opening ceremony – Ronny Tong Ka-wah, a member of Lam’s cabinet, turned down the invitation to attend.

“I would go if I could come back [to Hong Kong] across the bridge. But this arrangement didn’t look attractive to me,” he said.

Critics have called the bridge a “blood and sweat project”, noting that 11 workers died – the government puts the death toll at nine – and hundreds were injured building the Hong Kong section of the bridge.

Additional reporting by Sum Lok-kei and Kimmy Chung