。
Everything went well.
Literal
All-things well [adverbial-く] went.
万事うまくいった is the plain past tense of the set idiom 万事うまくいく ('everything goes well'). 万事 ('ten-thousand things,' 'all matters') is a formal idiomatic 'everything,' and うまくいく ('to go well, work out') is the standard verbal idiom for things proceeding smoothly. A common reflective summary after a successful event.