City of Portsmouth's talented Great Britain and England international will be looking to mix it with the fast elite racers in Wales in September.
His coach Vince Stamp managed to secure the entry through a friend and it has given the 17-year-old a good target to aim for in September.
He always enjoys the longer races and it will be his first 10k.
Wellington was comfortable in winning race four of the Lakeside 5k Series in Portsmouth with a time of 15min 40sec. That was only after he stretched away in the final 800m to get clear of his nearest rival Chichester's James Baker (15.59).
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The race to be first lady was hard-fought with Southampton's Sarah Kingston setting off in the lead and maintaining her advantage under pressure to win in 18.25 with City of Portsmouth's Emma Jolley second in 18.36.
For Wellington the next big aim will be to get a fast 10k time under his belt in Wales.
If it had been a faster race at the front for the Lakeside last Wednesday he would have liked to push for under 15 minutes.
Stamp said: '˜The plan is for Lachie to make his 10k debut on September 2 in Cardiff. It's a big race with 10,000 people.
'˜I've got him an entry into elite at the start so he will be at the sharp end and the target is to get him under 31 minutes. In my careerÂ I never got under 31 and I don't underestimate the level you have to be at to achieve it.
'˜Lachie is only just 17 but he is at the level to do that.
'˜It was ideal conditions for the Lakeside 5k I felt. No wind and the temperature had dropped a little bit.
'˜He enjoyed the win. It was a bit of fun for him and maybe the fifth race of the series at the end of August could be the perfect way to set him up for the 10k in Cardiff.'
Baker has now won the series overall prize after good consistent performances throughout having done three of the four races.
He's got a win, a second place and a third position so far with his times 15.48, 15.59 and 16.01. That has put him in a position where nobody can challenge him in race five.
City of Portsmouth's Callum Crook had a good run to finish fifth in the fourth event with 16.57.Â
Bradley Whitlock (18.59), William Campbell (19.08), Daisy Wilkinson (20.14) and Ryan Hawkins (20.15) were among the athletes to get new bests, while Holly Wilkinson finished third female and first under-15 (19.43).