Andy Murray gave coach Ivan Lendl the perfect welcome back with a fine win over France's Nicolas Mahut at Queen's Club in London.
The Briton, 29, saved set points in both sets as he won 7-6 (10-8) 7-6 (7-1) to reach round two of the Aegon Championships.
Lendl was courtside for the first time since 2014, having agreed last week to resume their working relationship.
Murray will face fellow Briton Aljaz Bedene after his win over Benoit Paire.
Slovenian-born Bedene made up 35 ranking places to beat the French world number 23 Paire 7-6 (8-6) 6-7 (7-9) 6-4 in two and a half hours.
Asked about Lendl, Murray told BBC Sport: "He doesn't really give many signs during the match. He's got quite a straight face.
"I started working with Jamie Delgado a few months ago and that's worked extremely well, and obviously I had some of my best years with Ivan a few years ago.
"I think it's a very strong team and I'm hoping they can help me win more major events."
Swiss second seed Stan Wawrinka earlier lost 6-2 7-6 (7-3) to Spain's Fernando Verdasco.
Murray finds his feet
Lendl had resumed his coaching role on Tuesday morning, directing the drills as Murray went through their first practice together for over two years.
The session was cut to just an hour because of the rain which has blighted the first two days at Queen's Club, leaving Murray a little short of time on the grass.
Mahut, ranked 51st, won a title on the surface 24 hours earlier in the Netherlands and looked the more sure-footed when the pair finally got on court just after 17:00 BST.
The Frenchman broke serve first but could not convert the next game from 40-0, and Murray came through a tense tie-break on his third set point.
Mahut had an opportunity at 8-7, failing to make a return of serve, but he moved 4-1 up in the second set and a furious Murray went close to smashing his racquet.
The Scot complained to the umpire about the conditions underfoot, and Mahut would later slip over, but Murray fought back to 5-5 and saved three more set points before dominating the second tie-break.
"It was tough," said Murray, a four-time winner at Queen's.
"Nico's a very accomplished grass-court player and because of the weather the last few days, we haven't been able to get on the grass too much to hit.
"It was a tricky first round and I'm glad I managed to get through."
Verdasco too sharp for Wawrinka
Wawrinka, 31, never looked comfortable on a greasy surface and struggled to cover the powerful forehand of his opponent.
Verdasco wrapped up the match - which was interrupted by rain - as Wawrinka's serve faltered during a tie-break.
"For sure conditions are difficult for everybody since a few days with the rain," said world number five Wawrinka.
"That's the same for everybody, but it was a tough match.
"Grass is always a challenging surface for my game. I need quite a lot of practice to play my best game."
Third seed Milos Raonic and Australian Nick Kyrgios will resume their match at one set all after darkness forced them from the court.
Verdasco will play Bernard Tomic next after the Australian extended his winning run over South African Kevin Anderson to five matches with a 6-3 6-4 victory.
British number five James Ward lost to Luxembourg's Gilles Muller 6-4 6-4. Compatriots Kyle Edmund and Daniel Evans' matches - against France's Gilles Simon and Paul-Henri Mathieu respectively - have been delayed until Wednesday.