By David Benoit

May 13, 2015 6:08 p.m. ET

DuPont Co.’s victory Wednesday in its proxy fight with Trian Fund Management LP was also a big win for the chemical company’s advisers including Goldman Sachs Group Inc.

Capping one of the most noteworthy and heated battles between an activist investor and a company in recent years, DuPont shareholders re-elected all of its sitting directors, rejecting a bid to add Trian’s Nelson Peltz and others to the board.

Goldman, credited by many on Wall Street with being the first bank to establish activism defense as a major client offering, was a key player in helping DuPont devise a strategy to fend off Trian—an effort whose success was far from guaranteed before the ballots were counted at the company’s annual meeting Wednesday in Wilmington, Del.

DuPont took an approach that a number of activism targets have eschewed lately: It refused to settle with Trian. That may give other companies in a similar situation more confidence to follow suit, bankers and lawyers said following the vote.

To be sure, DuPont had a stronger hand to play than others might, as its stock has performed well and Chief Executive Ellen Kullman is well respected by shareholders.

DuPont was advised by Goldman’s lead activism-defense adviser, William Anderson, as well as by members of its chemicals investment-banking team. Boutique investment bank Evercore Partners Inc. also advised DuPont. The company received legal advice from Skadden, Arps, Slate, Meagher and Flom LLP. Its proxy solicitor, tasked with making the company’s case to its shareholders, was Innisfree M&A Inc.

Trian worked with lawyers from Paul, Weiss, Rifkind, Wharton & Garrison LLP and proxy solicitor MacKenzie Partners Inc.

DuPont overcame recommendations from proxy-advisory firms Institutional Shareholder Services Inc. and Glass Lewis & Co., which sided with Trian. Large index funds decided to buck those recommendations, underscoring the potential limits of the advisory firms’ influence in campaigns involving the biggest companies.

“ISS has always been in the business of making voting recommendations, with our clients as institutional investors making the final vote decision,” a spokesman for the advisory firm said. “We stand by our analysis while respecting the decision of DuPont shareholders.”

For Goldman, the win is among its most high-profile in recent years and will likely blunt criticism the bank has received over losses its clients were dealt last year at Darden Restaurants Inc. and Sotheby’s, where activists won every seat they sought.

Another firm that is known for defending American corporations against the onslaught of shareholder activism in recent years is Wachtell, Lipton, Rosen & Katz. The law firm’s Martin Lipton in recent remarks appeared to question DuPont’s decision to stage such a spirited defense. Mr. Lipton, who wasn’t involved, said in a memo that companies should consider settling such battles.

He said later he didn’t mean DuPont should settle.

Write to David Benoit at david.benoit@wsj.com