Wu, greeting James Soong, chairman of the People First Party who arrived at the KMT campaign headquarters to congratulate Ma, said his party would seek to open merger talks with the ally as soon as possible.
Soong said he hopes the KMT will not let the nation down.
In response to Ma's victory, Huang Kun-huei, chairman of the once strongly pro-independence Taiwan Solidarity Union, said his party respects the people's choice.
He urged that the KMT, set to control both the administration and the parliament, respect the minority.
Chen became president in 2000 by defeating KMT candidate Lien Chan and independent contender James Soong.
Although Chen failed to win a majority of votes, the split of the same voter base by Lien and Soong -- who broke ranks with the KMT to mount the independent campaign -- gifted Chen with the victory.
In 2004 Lien mounted a comeback bid with Soong as his running mate.
But the president was re-elected by a razor-thin margin after he and Lu were injured in an election-eve shooting, which is believed to have won them sympathy votes.
Ma won on an anti-corruption and economy-boosting platform. He has promised to expand high-tech industrial ties between Taiwan and China.
Soochow University professor Liu Bih-rong, who specializes in cross-strait relations, was cited by the AFP as commenting that the landslide was unexpected.
"The election result shows Taiwan has grown into a more mature democracy," he said, predicting relations with China would improve at a faster pace.
"It shows that the Taiwanese people have given the KMT the mandate to open direct links and push for the one common market with China."
Better cross-strait ties was what businessman Wang Wen-ho was looking for when he cast his ballot for Ma at a Taipei high school, according to AP.
"The DPP has failed to cope with China's growth in eight years," he was cited by AP as saying. "We need to engage the mainland to improve the economy."
Hsieh, despite embracing his party's pro-independence cause, has also promised to accelerate cross-strait ties, but the scope in his promise was narrower than that of Ma's.
Hsieh also warned voters of the danger of one-party dominance if Ma was elected.
Taipei voter Chen Wei-ting, a 32-year-old banker, agreed with Hsieh, AP said. "I'm worried that if one party had the Legislature and presidency, there could be a lot of trouble."
But the man's wife, Chen Chia-chia, a 25-year-old businesswoman, said she supported Ma. "The KMT did a good job when they were in power before, so I think everything will be OK," she was cited as saying.
