World number one Trump made breaks of 56 and 86 in a 3-1 win over Chinese teenager Fan Zhengyi before compiling 70 in a 3-0 victory over David Lilley.
A 2-2 draw with 1994 Masters champion Alan McManus saw Trump enjoy further runs of 59 and 71 to progress as Group One winner, three points clear of second-placed Fan.
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“A few of the players gave me the games and I didn’t have to work that hard to get over the line,” said 2019 world champion Trump.
“I made a few good breaks and some good one-visits. I knew coming that I’d barely practiced so I was looking to get through the group.
"There are a lot of tournaments coming up, it will be a strange old season and a lot of time spent in Milton Keynes.
“You have to appreciate every tournament at the moment and even though I haven’t practiced that hard I’m still trying hard and trying my best to get through.”
Group Two winner Day began the season in style with a 147 break in the fourth frame of his 3-1 victory over Rod Lawler.
It was the second maximum of his career as the two-times ranking event winner became only the second Welshman after Mark Williams to record a maximum in competitive action.
“I didn’t start thinking about it until I was on about 48, and then I thought; they’re perfect really,” said Day.
“The last shot on the pink was a bit touch and go but then the black was a lot higher on the black than you want to be. It’s nice to do a 147, so it’s nice to do one, it’s been a while since my last one in China six years ago."
Day pushed on from that outstanding start as he hit 60 and 81 in a 3-0 win over Paul Davison.
He also ran in a 95 against fellow Welshman Matthew Stevens, but knocks of 57 and 61 saw the unbeaten Stevens complete a 3-1 win.
It was not enough to deny Day a place in the next group phase as he earned £3000 to win Group Two.
Championship League results
Sunday 13 September
- Judd Trump 3-1 Fan Zhengyi
- Alan McManus 1-3 David Lilley
- Alan McManus 2-2 Fan Zhengyi
- Judd Trump 3-0 David Lilley
- David Lilley 0-3 Fan Zhengyi
- Judd Trump 2-2 Alan McManus
- Ryan Day 3-1 Rod Lawler
- Matthew Stevens 2-2 Paul Davison
- Matthew Stevens 2-2 Rod Lawler
- Ryan Day 3-0 Paul Davison
- Matthew Stevens 3-1 Ryan Day
- Rod Lawler 3-0 Paul Davison